Manchester United will play Belgium's Club Brugge and Celtic have been drawn against Swedish side Malmo in the Champions League play-off round.
Brugge finished top of the Belgian league last season but were second in the title play-offs, while Malmo are sixth in the Swedish league.
The first legs of the play-off ties will take place on 18-19 August, with the second matches on 25-26 August.
Southampton face Danes FC Midtjylland in the Europa League play-off round.
Ronald Koeman's side, who beat Vitesse Arnhem in the last round, are at home for the first leg on 20 August, before travelling to Denmark a week later.
The winners of the Champions League and Europa League play-off rounds will progress to the group stages of their respective competitions.
|Champions League play-off round draw|
|Astana(Kazakhstan) v APOEL Nicosia (Cyprus)||Lazio (Italy) v Bayer Leverkusen (Germany)|
|Skenderbeu (Albania) v Dinamo Zagreb (Croatia)||Manchester United (England) v Club Brugge (Belgium)|
|Celtic (Scotland) v Malmo (Sweden)||Sporting Lisbon (Portugal) v CSKA Moscow (Russia)|
|Basel (Switzerland) v Maccabi Tel Aviv (Israel)||Rapid Vienna (Austria) v Shakhtar Donetsk (Ukraine)|
|BATE Borisov (Belarus) v Partizan Belgrade (Serbia)||Valencia (Spain) v Monaco (France)|
|Europa League play-off round draw|
|Altach (Austria) vs. Belenenses (Portugal)||Panathinaikos (Greece) vs. Qabala (Azerbaijan)|
|Milsami Orhei (Moldova) vs. Saint-Etienne (France)||Lech Poznan (Poland) vs. Videoton (Hungary)|
|Zilina (Slovakia) vs. Athletic Bilbao (Spain)||Southampton (England) vs. Midtjylland (Denmark)|
|Jablonec (Czech Republic) vs. Ajax (Netherlands)||Dinamo Minsk (Belarus) vs. Salzburg (Austria)|
|Steaua Bucharest (Romania) vs. Rosenborg (Norway)||Astra Giurgiu (Romania) vs. AZ Alkmaar (Netherlands)|
|Young Boys (Switzerland) vs. Qarabag (Azerbaijan)||Rabotnicki (Macedonia) vs. Rubin Kazan (Russia)|
|Zorya Luhansk (Ukraine) vs. Legia Warsaw (Poland)||Odds (Norway) vs. Borussia Dortmund (Germany)|
|Molde (Norway) vs. Standard Liege (Belgium)||Slovan Liberec (Czech Republic) vs. Hajduk Split (Croatia)|
|Viktoria Plzen (Czech Republic) vs. Vojvodina (Serbia)||Krasnodar (Russia) vs. HJK Helsinki (Finland)|
|PAOK (Greece) vs. Brondby (Denmark)||Atromitos (Greece) vs. Fenerbahce (Turkey)|
|Bordeaux (France) vs. Kairat Almaty (Kazakhstan)||Thun (Switzerland) vs. Sparta Prague (Czech Republic)|