La Rochelle and Leinster will play a repeat of their epic Heineken Champions Cup final when they meet in the 2023-24 pool stage.
The French side have won back-to-back Champions Cups, beating Leinster in each of the past two finals.
They defeated the Irish team 27-26 in May having been 17-0 down at half time.
Both clubs are in Pool 4, alongside Premiership clubs Leicester Tigers and Sale Sharks, as well as Stade Francais and Stormers from South Africa.
Premiership champions Saracens are in Pool 1, as are Bristol Bears and Connacht, while Bath and Harlequins are in Pool 2 along with Cardiff Rugby and Ulster.
Exeter Chiefs and Northampton Saints are in Pool 3 with two-time champions Munster and last year's Challenge Cup runners-up Glasgow Warriors.
The European Rugby Champions and Challenge Cup competitions will return to a multi-pool format for the 2023-24 season.
The Champions Cup has 24 teams split into four pools of six, with the 18-team Challenge Cup being divided into three pools of six. Each team plays four games in their pool, and will not face the team from their same nation or league who they have been drawn in a group with.
The first round of fixtures will begin on Friday, 8 December, six weeks after the final of the 2023 Rugby World Cup in France, which runs 8 September to 28 October.
The 2024 finals will take place at Tottenham Hotspur Stadium 24-25 May.
2023-24 Champions Cup pool stage
Pool 1: Saracens, Union Bordeaux-Begles, Bulls, Bristol Bears, Connacht, Lyon
Pool 2: Toulouse, Cardiff, Bath, Racing 92, Harlequins, Ulster
Pool 3: Munster, Aviron Bayonnais, Glasgow Warriors, Exeter Chiefs, Toulon, Northampton Saints
Pool 4: La Rochelle, Leinster, Stade Francais, Leicester Tigers, Stormers, Sale Sharks
British and Irish clubs discover Challenge Cup opponents
The draw for the second-tier Challenge Cup pool stage took place prior to the Champions Cup, with Premiership clubs Gloucester and Newcastle Falcons learning their opponents.
Newcastle were drawn in Pool 2 alongside Welsh club Ospreys, Italian side Benetton Rugby and Lions from South Africa, as well as two French clubs in USAP and Montpellier.
Gloucester are in Pool 3 with Edinburgh Rugby, Scarlets, two Top 14 clubs in Castres and Clermont Auvergne, and one of two as yet unknown invitee clubs to be determined at a later date.
Toulon are Challenge Cup holders after overpowering first time finalists Glasgow Warriors 43-19 in the 2023 final.
2023-24 Challenge Cup pool stage
Pool 1: Invitee 1, Section Paloise, Dragons, Zebre, Oyannax, Sharks
Pool 2: Ospreys, USAP, Newcastle Falcons, Lions, Montpellier, Benetton Rugby
Pool 3: Edinburgh, Castres, Clermont Auvergne, Invitee 2, Gloucester, Scarlets