Croatia are bidding to reach the final of the competition for the first time in their history, having failed to even make it past the group stages since their third-placed finish at France 1998.
England, meanwhile, are appearing in their first World Cup semi-final since 1990 and know that victory would take them to the final for only the second time ever, and the first since they lifted the trophy in 1966.
The winners will face France in the final on Sunday.
Make sure you don't miss a moment of the action courtesy of our live text coverage below.
CROATIA: Subasic; Vrsaljko, Lovren, Vida, Strinic; Brozovic, Modric, Rakitic; Perisic, Rebic, Mandzukic
ENGLAND: Pickford; Walker, Stones, Maguire; Trippier, Henderson, Alli, Young; Lingard, Sterling; Kane
It is semi-final heartbreak once again for England as they crash out at the hands of Croatia following extra time. There may be questions of 'what if?' after England spurned a few chances in the first half, but Croatia were by far the better team in the second half and on the balance of the whole game, you'd have to say that Croatia deserve the victory.
Trippier got England off to a dream start with a fifth-minute free kick which flew into the top corner, but Perisic levelled things up with a little over 20 minutes remaining. The game then went to extra time, and it was Croatia who had the legs with Mandzukic scoring the 109th-minute winner.
Congratulations to Croatia, but England's dream World Cup run is over! Thanks for joijing our live coverage of the match!
120+4 min CROATIA ARE THROUGH TO THE WORLD CUP FINAL!
120+4 min ENGLAND ARE OUT OF THE WORLD CUP!
120+4 min ET England have a free kick with 30 seconds of stoppage time left. Last chance saloon...
120+2 min ET It must be said that Kane has really struggled tonight. It looks as though he is carrying an injury or is simply exhausted as he has not been anywhere near as sharp as he usually is.
120+1 min ET There will be FOUR minutes of added time at the end of this match.
120 min ET CHANCE! Half a chance for Kramaric as he bursts forward into space, but he doesn;t look up, goes for goal himself and fires his effort into the side-netting.
119 min ET CROATIA SUB: One more change from Croatia as Modric is replaced by Milan Badelj.
117 min ET England will need to end this game with 10 men too as Trippier has been carried off with what looks like a groin injury.
116 min ET SAVE! Brozovic tires his luck from distance and it is an easy enough save for Pickford, although he almost spills it at the feet of Vida before collecting it at the second attempt.
115 min ET CROATIA SUB: Mandzukic limps off to be replaced by Vedran Corluka.
114 min ET Croatia are just keeping the ball now, and England have little choice but to go chasing it, which is opening up more spaces behind them in midfield. Croatia win a corner, though.
112 min ET ENGLAND SUB: A final throw of the dice for England as Jamie Vardy replaces Kyle Walker.
111 min ET Less than 10 minutes remaining in this semi-final now, and it is the biggest 10 minutes of these players' lives. Can England add one final twist to the tale or has Mandzukic done enough to send Croatia into the final of the World Cup?
109 min ET Heartbreak for England as Croatia take the lead in the early stages of this second period of extra time. It is more tired defending from England, who are finally punished for their sloppy defender.
A poor clearance sends the ball looping into the air and it is nodded back hopefully into the box. Stones is caught sleeping for a second and that is enough for Mandzukic to get the wrong side of his man and sweep his finish past Pickford.
109 min ET GOAL! Croatia 2-1 England (Mario Mandzukic)
108 min ET CHANCE! England just cannot go to sleep like this. It is the easiest of corners as Modric plays a low pass into the box for Brozovic, who has escaped the attentions of Lingard. Thankfully for England, Brozovic blazes his effort wide of the near post.
106 min ET KICKOFF: Croatia get us back underway for the second period of extra time. A huge 15 minutes awaits for both teams!
Incredible scenes at the end of that first period of extra time, with Pickford making a remarkable save to perhaps keep England in the World Cup. Just 15 minutes to go now, and if nothing changes then we will have penalties!
105+4 min ET HALF TIME IN EXTRA TIME: Croatia 1-1 England
105+2 min ET WHAT A SAVE! Jordan Pickford, take a bow! A brilliant ball from Perisic seems to put the ball on a plate for Mandzukic from point blank range, but Pickford flies out and makes an incredible stop. It is brave from the keeper, who clatters into Mandzukic, but it is a massive, massive stop from the Everton man. Incredible.
105+1 min ET Perisic has been Croatia's most dangerous player tonight and he makes his way down the left again here before pulling the ball back for Kramaric. Kramaric goes for goal first time, but Dier makes a huge block.
105 min ET There will be two minutes of added time at the end of this first period of extra time.
103 min ET This has been better from England in extra time so far. They were second best for much of the second half, but look to have regained an element of control over the game here. It is still balanced on a knife edge, though.
101 min ET CROATIA SUB: Another change from Croatia here as Andrej Kramaric replaces Rebic.
101 min ET Rashford tracks back well on Vrsaljko and slides in, but the full-back sticks his leg out to ensure he is caught and buys the free kick in a good crossing position...
99 min ET OFF THE LINE! England are inches away from regaining the lead! It comes from the usual route of a set piece as Stones is left completely unmarked to meet Trippier's delivery. He flicks it towards goal, but Vrsaljko is there to clear the ball off the line!
97 min ET ENGLAND SUB: England make their third change as Eric Dier replaces Henderson. England have one more change remaining due to the new rules allowing an extra one in extra time.
96 min ET YELLOW CARD! Rebic goes into the book for a poor challenge on Rose. As it turns out he wasn't given one earlier, that instead went to Mandzukic.
95 min ET CROATIA SUB: Croatia finally make their first change of the evening, and it is an enforced one as Strinic limps off to be replaced by Josip Pivaric.
93 min ETA little better from England in the very early stages of extra time as they keep hold of the ball for longer than they managed for much of the second half, and in better positions too.
91 min ET KICKOFF: England get us back underway for the first half of extra time, and they have made a change in the interval with Danny Rose replacing Young.
90+3 min We go to extra time!
90+3 min END OF 90 MINUTES: Croatia 1-1 England
90+2 min CHANCE! It is half a chance for Kane as he meets Trippier's free kick with a clear header, but doesn't make good enough contact as it bounces wide.
90+1 min There will be THREE minutes of added time... and England have a free kick in a good crossing position!
90 min The pressure is starting to build again before Lovren, of all people, tries his luck from 35 yards and blazes it high and wide of the target.
88 min Just two minutes of normal time remaining in this match, and England would be the happier of the two teams to reach extra time right now. This is unbearably tense!
86 min Croatia are just swarming all over England at the moment. They have the wind in their sails whereas it is England who are looking tired and panicky. Perisic in particular is everywhere.
84 min CHANCE! England are living very dangerously now. Pickford comes to claim an aerial ball into the ball but doesn't get a good punch on it under pressure from Mandzukic. The ball drops to Perisic, but he cannot steer it into the empty net.
I can't take this much longer!
83 min CHANCE! Another chance for Croatia as Brozovic dinks the ball into the path of Mandzukic, who takes it down on his chest before releasing a volley which stings the palms of Pickford.
82 min I hate to say it, but the most likely winner right now looks to be Croatia, because of moments like below. England are a bit all over the place at the back at the moment...
80 min Suddenly a chorus of 'God Save The Queen' rings out around the stadium as the England fans try to stir their team into life. Just 10 minutes remaining in this semi-final now!
78 min SHOT! Better from England now as Rashford makes headway down the left. Kane turns down the shot and gives it to Henderson, who tries a volley at the second attempt but fires it over the crossbar.
77 min CHANCE! Half a chance for England as they look to stem the tide of Croatia chances. Lingard gets down the right flank and plays a shot/cross into the box which evades everyone.
76 min It is all Croatia now, and this is the goal which has changed everything. A question mark over dangerous play, perhaps, but for me it is a perfectly valid goal...
73 min SHOT! England are on the ropes and losing concentration here. Croatia take a quick corner with England sleeping and it takes a good clearance from Maguire to deny Perisic again. The ball only goes as far as Brozovic, who fires his effort over the crossbar.
72 min OFF THE POST! England are really testing their luck here! Perisic picks the ball up on the left and beats Walker all ends up before drilling a low strike across goal which beats Pickford before hitting the far post. The ball bounces back out to Rebic, but he can only divert the ball into the arms of Pickford.
70 min Just 20 minutes remaining in this second half now, and England need to pick themselves up. They have not been anywhere near their best in this second half and they need to rediscover the form which served them so well before the interval.
68 min There have been one or two signs of this, but Croatia have levelled things up with just over 20 minutes remaining through a clever finish from Perisic!
Vrsaljko is given all the time in the world to swing his cross into the box and Walker lines it up all the way for a diving header clear. However, Perisic gets in front of him and produces an acrobatic effort to glance his finish past Pickford with the outside of his foot.
68 min GOAL! Croatia 1-1 England (Ivan Perisic)
68 min Kane collects the ball down the right channel and has no-one in support so tries his luck from an impossible angle, and his volley slams into the side-netting.
67 min Walker is back up and looks like he will be fine to continue. It will take a lot more than that to keep him out of this match!
65 min CHANCE! Croatia have one of their best chances of the night so far as the ball breaks to Perisic on the edge of the box, but Walker throws himself in the way of it to make a fine block. It looks like that one hurt though - and I think every man will sympathise with him!
63 min Henderson slides a clever pass through for Sterling, who breaks into the box and tries to stand up Vida. Vida hangs a leg out and Sterling goes down, but the referee says no penalty. It looks like the right decision on first viewing.
61 min Perisic swings a cross into the box which Trippier can only clear as far as Rakitic, but the Barcelona man swipes at his difficult half-volley and slices it well off target.
59 min England are just beginning to hack at the ball a little here, with Walker slicing an attempted clearance behind for a cheap corner. There are just a few signs of nerves beginning to settle in.
58 min Strinic breaks into the England box down the left flank but his delivery is poor and Stones is able to clear.
57 min Trippier almost pulls another memorable moment out of the bag, controlling a brilliant low cross into the box from Walker's aerial pass over the top. Kane throws himself at it, but it is good defending from Croatia.
56 min SHOT! The ball drops to Lingard kindly following some route one football. Kane nods it on to Sterling, to tees it up for Lingard, but his effort takes a deflection and loops over the bar for a corner.
54 min YELLOW CARD! Walker picks up a cheap yellow card for keeping the ball away from Croatia when they wanted to take a quick throw-in.
53 min Kane tries to dip inside between two defenders and is sandwiched, but the referee decides against a free kick in a dangerous position. Harsh decision from the ref there.
51 min YELLOW CARD! Mandzukic follows Rebic into the book at the start of this second half for a challenge on Walker once again.
48 min YELLOW CARD! Rebic becomes the first name in the book this evening for an extended arm on Walker while contesting a header.
46 min KICKOFF: Croatia get us back underway for the second half! Can England hold on to reach the WORLD CUP FINAL?!
What a first half for England, and the only down side for them is that they are not further ahead at the break. Aside from that, though, England could barely have wished for anything more.
Croatia, for their part, have been disappointing and slow to get going, but England also deserve credit for the way they have played. They took the lead early on and now find themselves just 45 minutes away from the World Cup final.
45+1 min Almost a late fright for England as an incident in the final free kick of the half is taken to VAR after the referee has blown his whistle. All the England players are off the pitch, and thankfully no penalty is given.
45+1 min HALF TIME: Croatia 0-1 England
45 min There will be one minute of added time at the end of this first half.
45 min England almost shoot themselves in the foot here as a mix-up between Walker and Stones is followed by a nervy clearance from Pickford. Croatia win it back and play it to Rakitic, who tries the flick the ball inside Gazza-esque before being crowded out.
43 min This plays right into England's hand; Vrsaljko ends a long passing move by going for goal from a long, long way out, and he slices it well off target.
42 min England could well be further ahead here, but right now their priority must be getting to half time with this lead intact. Croatia have grown into the game a little, but England remain in control courtesy of that early Trippier free kick.
40 min Vida is getting the treatment from Russian fans whenever he gets on the ball, and it is no surprise really considering his comments on Ukraine which really drew the ire of the host nation.
38 min That is Kane and Lingard who have now missed clear chances for England, and one can only hope that they don't live to rue them. Gazza in 1990, when he just couldn't reach the ball, springs to mind.
36 min CHANCE! Another chance goes begging for England, who should be further ahead here! Kane gives the ball out to Alli, who in turn plays a square ball to Lingard on the edge of the box. Lingard has the time and space to pick his spot, but he doesn't get his foot around it and fires his effort wide of the target when he should have done better.
34 min This is Croatia's best spell of the match right now and the nerves will be beginning to jangle for England. A second goal would really settle those nerves, but they can be pleased with their performance so far.
32 min SAVE! Pickford has his first save to make as Stones cuts out a dangerous ball into the box and Maguire can only poke it as far as Rebic. Rebic curls an effort towards goal, but it is straight at Pickford.
30 min CHANCE! Huge chance for England to double their advantage, and it falls to the man they would want too! The ball is slipped through to Kane and he only has Subasic to beat, but he cannot bend the ball around the keeper. The loose ball squirms away but Kane picks it up against and tries to squeeze it in from a tight angle, only for it to take a deflection off the defender, post and loop away to safety.
29 min Croatia have certainly settled after that tricky start, but they are yet to find their usual rhythm here.
27 min Brilliant pace from Sterling as he gives Lovren a big head start but still beats him to the ball. He then cuts inside and draws a rash foul from the Liverpool man, giving England another free kick in a crossing position.
25 min We're 25 minutes into this first half now and England will be delighted so far. They have the early goal, Pickford is yet to make a save and they are looking dangerous on the break too. Very promising signs.
23 min SHOT! Perisic tires his luck from range once again as the ball bounces kindly for him on the half-volley, but he doesn't catch it right and it is never troubling Pickford.
22 min A defensive error almost gifts England a good chance as they give the ball straight to Sterling, but his pass inside to Kane finds the Tottenham man offside.
21 min Croatia are beginning to grow into this game a little now and Rebic looks to have created space to shoot from just outside the box, but Stones darts out to throw himself in front of the ball.
19 min SHOT! Croatia have their first effort of the night as Perisic tries his luck from range, but Pickford looks to have it covered on its way wide. Perisic wants a corner - and he should have one as it took a nick off Walker on the way through - but the referee gives a goal kick.
18 min The Bury Beckham strikes again!
16 min Croatia just have not been able to get into this game at all so far. England have made a brilliant start and have been on top almost from the first whistle. A second goal would do wonders for them here.
14 min CHANCE! Another corner, and another Maguire header. This one is a better chance for the Leicester man, though. He gets up well and plants a downward header a yard or so wide of the post.
12 min Young drifts a corner into the area and it is no surprise to see Maguire smashing his way through to get his head on it. He cannot keep his effort down, though, and the referee blows for a free kick anyway.
11 min Feast your eyes on this beauty from Trippier - only the third man to score for England in a World Cup semi-final, joining Sir Bobby Charlton and Gary Lineker. Exalted company indeed!
9 min The first piece of Croatia pressure comes as they win a corner and England make a bit of a mess of clearing it. They soon break out, though, and Kane almost releases Sterling with a ball forward which Vrsaljko does well to cut out.
7 min England can smell blood here! They have come flying out of the blocks and Sterling has just threatened a couple of times with his pace in behind too. The onus is on Croatia now, but England are looking to put this game to bed early.
5 min What a start for England! It is an absolute dream for Southgate's side as they take the lead after just five minutes, and it is a stunner from Kieran Trippier!
The Tottenham full-back bends the free kick over the wall and into the top corner, leaving Subasic no chance whatsoever! What a time to get your first goal for England!
5 min GOAL! Croatia 0-1 England (Kieran Trippier)
4 min Lingard brings the ball down majestically and knocks the ball inside for Alli, who is brought down by Modric. Free kick to England in a very good position...
3 min The England fans are out in force for this match; there were around 3,400 in Samara for the quarter-final, but there is reportedly at least 10,000 here for this semi-final. They are making themselves heard too!
1 min KICKOFF: Here we go! England get us underway in Moscow!