Champions Cup holders Toulouse will face three former winners and the Sharks in next season's groups, after tournament organisers made the draw for the pool stages on Tuesday.
The French Top 14 champions beat Leinster 31-22 in May's final to claim a record sixth crown and will play Exeter, Leicester and Ulster in Pool 1, with Bordeaux-Begles and the Challenge Cup winners from South Africa the Sharks also in the group.
Teams will come up against all the sides in their pool apart from a club from the same league.
In Pool 2, Irish province Leinster will once again play La Rochelle in a repeat of the 2022 and 2023 finals.
The highlight of Pool 3 is a re-run of 2000's decider as Munster face Northampton while three-time winners Toulon are in Pool 4 alongside United Rugby Championship holders Glasgow.
In the second-tier Challenge Cup, French side Vannes, newly-promoted to the Top 14, are in Pool 3 in their debut season alongside Georgians Black Lion, French club Bayonne, Welsh side Scarlets, Scottish outfit Edinburgh and Gloucester from England.
The fixtures will be announced at a later date, with games to be played on the weekends of December 6-8, December 13-15, January 10-12 and January 17-19.
The Champions Cup final will be held on May 24 at the Millenium Stadium in Cardiff, the city that hosted the first ever final in 1996.
The Challenge Cup's decider will take place in the same ground but on the previous day.
Champions Cup
Pool 1: Toulouse (FRA), Bordeaux-Begles (FRA), Sharks (RSA), Exeter (ENG), Leicester (ENG), Ulster (IRL)
Pool 2: Leinster (IRL), Clermont (FRA), La Rochelle (FRA), Bristol (ENG), Treviso (ITA), Bath (ENG)
Pool 3: Northampton (ENG), Munster (IRL), Bulls (RSA), Stade Francais (FRA), Saracens (ENG), Castres (FRA)
Pool 4: Glasgow (SCO), Racing 92 (FRA), Sale (ENG), Stormers (RSA), Toulon (FRA), Harlequins (ENG)
Challenge Cup
Pool 1: Cardiff (WAL), Connacht (IRL), Cheetahs (RSA), Perpignan (FRA), Lyon (FRA), Zebre (ITA) Pool 2: Montpellier (FRA), Pau (FRA), Newcastle (ENG), Dragons (WAL), Lions (RSA), Ospreys (WAL)
Pool 3: Vannes (FRA), Black Lion (GEO), Bayonne (FRA), Scarlets (WAL), Edinburgh (SCO), Gloucester (ENG)