Pro 14 champions Leinster have been drawn in the same group as Montpellier and Northampton Saints for this season's Champions Cup, while Munster have been drawn against French giants Clermont and Harlequins.
Meanwhile, current champions Exeter Chiefs will begin the defence of their title in a group with four-time winners Toulouse and Glasgow Warriors, following Wednesday's draw in Lausanne, Switzerland.
Runners-up Racing 92 will face Connacht and English side Harlequins.
Ulster meanwhile will take on four time winners Toulouse and Gloucester Rugby.
Bordeaux Begles, who led France's Top 14 league when the 2019-20 season was abandoned due to the Covid-19 pandemic, face Welsh team Dragons and Northampton Saints.
The format for next season's Champions Cup was overhauled because of the pandemic, with the group and knockout stages expanded.
The 2020-21 competition will be contested by 24 clubs - four more than in regular seasons - with the eight top-ranked sides from the Premiership, Pro14 and Top14 competitions.
The teams have been split into two pools of 12, with four rounds of games held over four weekends starting from December 11th, in a home and away format.
The top four teams from each pool advance to the knockout stages, which begin with home-and-away quarter-finals, while the bottom four drop into the Challenge Cup.
The Champions Cup semi-finals will be held on the weekend of April 30th, with the final at the Stade Velodrome in Marseille on May 22nd.
Your 2020/21 #HeinekenChampionsCup Pools 🤩
Reigning champs @ExeterChiefs and semi-finalists @StadeToulousain are drawn together 🤜🤛
While there'll be a re-run of the 2011 Final between @leinsterrugby and @SaintsRugby again..
More info 👉 https://t.co/B9Ly77tVcZ pic.twitter.com/GT6InxpeFf
— Heineken Champions Cup (@ChampionsCup) October 28, 2020
Pool A (opponents in brackets)
Union Bordeaux Begles (Dragons, Northampton Saints)
Leinster (Montpellier, Northampton Saints)
Wasps (Dragons, Montpellier)
Bath (La Rochelle, Scarlets)
Edinburgh (La Rochelle, Sale Sharks)
Toulon (Sale Sharks, Scarlets)
La Rochelle (Bath, Edinburgh)
Sale Sharks (Edinburgh, Toulon)
Scarlets (Bath, Toulon)
Dragons (Union Bordeaux Begles, Wasps)
Montpellier (Leinster, Wasps)
Northampton Saints (Bordeaux-Begles, Leinster)
Pool B (opponents in brackets)
Exeter Chiefs (Glasgow Warriors, Toulouse)
Lyon (Glasgow Warriors, Gloucester)
Ulster (Gloucester Rugby, Toulouse)
Bristol Bears (Clermont Auvergne, Connacht)
Munster (Clermont Auvergne, Harlequins)
Racing 92 (Connacht, Harlequins)
Clermont Auvergne (Bristol Bears, Munster)
Connacht (Bristol Bears, Racing 92)
Harlequins (Racing 92, Munster)
Glasgow Warriors (Exeter Chiefs, Lyon)
Gloucester (Lyon, Ulster)
Toulouse (Exeter Chiefs, Ulster)