Celtic will face Czech side Slavia Prague in the Champions League play-off round should the Scots defeat Cluj in their third qualifying round.
Neil Lennon's side face the Romanians in the first leg away from home on Wednesday.
Should Celtic lose, they will drop into the Europa League play-off stage.
Slavia qualified directly to the Champions league play-off stage after winning their domestic title for a fifth time.
Last season's beaten semi-finalists, Ajax, will face APOEL of Cyprus or Qarabag of Azerbaijan if the Dutch side overcome PAOK of Greece.
Steau Bucharest, Romania's 1991 winners, will face Young Boys of Switzerland if they defeat Denmark's Copenhagen.
Meanwhile, 1987 winners Porto, who qualified as runners-up in Portugal, will take on Istanbul Basaksehir of Turkey or Olympiakos of Greece if they defeat Russian side Krasnodar.
More to follow.
Champions League play-off round draw
Champions path
Dinamo (Croatia) or Ferencvaros (Hungary) v Maribor (Slovenia) or Rosenborg (Norway)
Celtic or Cluj (Romania) v Slavia Prague (Czech Republic)
Young Boys (Switzerland) v Red Star Belgrade (Serbia) or Copenhagen (Denmark)
APOEL (Cyprus) or Qarabag (Azerbaijan) v PAOK (Greece) or Ajax (Netherlands)
League path
Basel (Switzerland) or LASK (Austria) v Bruges (Belgium) or Dinamo Kiev (Ukraine)
Istanbul Basaksehir (Turkey) or Olympiakos (Greece) v Krasnodar (Russia) or Porto (Portugal)
Matches to be played on 20/21 and 27/28 August
Source: bbc.com