Holders Bordeaux-Begles and last season’s finalists Northampton Saints have been drawn in Pool 4 for the 2025-26 Investec Champions Cup.
In May, Bordeaux defeated Saints 28-20 in Cardiff to lift their first Champions Cup title.
Premiership semi-finalists Bristol Bears, Scarlets, Top 14 side Pau and United Rugby Championship (URC) runners-up Bulls are also in Pool 4.
Three-time winners Saracens are in Pool 1 alongside record six-time champions Toulouse.
They are joined by Glasgow Warriors, Sale Sharks, Clermont Auvergne and South African side Sharks.
Premiership champions Bath, who won last year’s Challenge Cup, are in Pool 2 with Munster, Gloucester, Edinburgh, Castres and three-time winners Toulon.
In Pool 3, Leinster, who lost to Northampton in last year’s semi final, again are drawn in the same pool as Ronan O’Gara’s La Rochelle, who defeated the Irish province in back-to-back finals in 2022 and 2023.
Leo Cullen’s team squeezed past the Top 14 side 16-14 in last year’s pool stage.
Leicester Tigers and Harlequins are also in Pool 3, with Bayonne and South African side Stormers.
Each team will play four different opponents in the pool stage, but not teams from their own league, with fixtures still to be announced.
In the Challenge Cup, Ulster, who finished 14th in last season’s URC have been drawn in the same pool as Parisian rivals Racing 92 and Stade Francais in Pool 3.
Ospreys and Connacht have a kinder draw in Pool 1, which contains Georgian side Black Lion.