Celtic are expected to face Linfield in the Champions League qualifying round after UEFA's preliminary draw was held on Monday in Nyon.
Brendan Rodgers' men went unbeaten domestically in a record-breaking 2016-17 season in which they won all three titles available in the coach's first year in charge.
The Scottish side reached the group stage of the Champions League last year but finished bottom in a tough draw with Barcelona, Manchester City and Borussia Monchengladbach.
Linfield are heavy favourites against San Marino side SP La Fiorita in the first qualification round, which they'll need to win to book their fixture with Celtic.
The minnows of the Champions League face off against each other later this month and again in the return fixtures at the start of July.
There's a notable all-British tie when Welsh champions The New Saints face Gibraltar's Europa FC.
Celtic are the biggest team in the draw, with the highest coefficient - how UEFA ranks clubs in continental competition - and the only former European champions at this early stage of the tournament.
Having been drawn against Hibernians FC of Malta or Estonia's FCI Tallinn, Red Bull Salzburg could also cause UEFA a headache.
The governing body's statutes prevent owners from controlling more than one club per season in its competitions, with the higher ranked side in such a situation being given preference.
That would mean the Austrian champions could retain a place in the group stage, should they advance that far, at the expense of RB Leipzig, the Bundesliga's surprise runners-up.
UEFA were last month quoted as saying: "All criteria, including matters of ownership, will be verified for each club by UEFA only once we have received the competition entry forms and documentation from the national football associations and clubs, following the end of the season in the respective leagues."
Irish champions Dundalk have been drawn against Norwegian side Rosenborg.
Following a third qualification round in which the likes of Nice and Ajax join the fray - that draw is on July 14 - the Champions League play-off round big guns join the elimination round in a draw on August 4.
Liverpool, Sevilla, Napoli, Hoffenheim and Sporting are the teams who enter at the play-off stage.
The Champions League group stage draw will take place on August 24 once all of the qualification and play-off matches are taken care of.
Should Liverpool win their two-legged tie, England could have five teams in the Champions League group stage for the first time ever due to Manchester United's win in the Europa League final.
First qualifying round
Vikingur (FRO) v Trepca 89 (KOS)
Hibernians (MLT) v FCI Tallinn (EST)
Alashkert (ARM) v FC Santa Coloma (AND)
The New Saints (WAL) v Europa (GIB)
Linfield (NIR) v La Fiorita (SMR)
– First legs to be played June 27/28, second legs July 4/5
Second qualifying round
APOEL (CYP) v Dudelange (LUX)
Zalgiris (LTU) v Ludogorets Razgrad (BUL)
Qarabag (AZE) v Samtredia (GEO)
Partizan Belgrade (SRB) v Buducnost Podgorica (MNE)
Hibernians (MLT) or FCI Tallinn (EST) v Salzburg (AUT)
Sheriff (MDA) v Kukes (ALB)
Astana (KAZ) v Spartaks Jurmala (LAT)
BATE Borisov (BLR) v Alashkert (ARM) or FC Santa Coloma (AND)
Zilina (SVK) v FC Copenhagen (DEN)
Hapoel Beer-Sheva (ISR) v Budapest Honved (HUN)
Rijeka (CRO) v The New Saints (WAL) or Europa (GIB)
Malmo (SWE) v Vardar (MKD)
Zrinjski (BIH) v Maribor (SVN)
Dundalk (IRL) v Rosenborg (NOR)
FH Hafnarfjordur (ISL) v Víkingur (FRO) or Trepca 89 (KOS)
Linfield (NIR) or La Fiorita (SMR) v Celtic (SCO)
IFK Mariehamn (FIN) v Legia Warsaw (POL)