The BT Sport website is closing - Activate discovery+ nowSep 23
Leinster will open their Champions Cup campaign against La Rochelle - their vanquishers in the last two finals in the competition.
Both matches saw the Irish side lead heading into the closing stages, only for a French try to break the hearts of Leo Cullen's men, with the most recent meeting seeing Ronan O'Gara's charges overturn a 17-0 deficit to win 27-26 in Leinster's own backyard, the Aviva Stadium.
The Pool 4 sides clash at Stade Michel Deflandre on Sunday 10 December.
This year's competition will see 24 teams split into four pools of six, as opposed to the two pools of 12 last term.
Pool 1 outfits Saracens and Bristol Bears first face the Vodacom Bulls and Lyon respectively, with Bordeaux-Begles and Connacht making up that section.
Bath take on Ulster and Harlequins visit Racing 92 in their openers in Pool 2, which also includes Cardiff Rugby and Toulouse, who have won the title a record five times.
2019/20 winners Exeter Chiefs and Northampton Saints begin their campaigns against Toulon and Glasgow Warriors, the pair who contested last season's Challenge Cup final. Munster and Bayonne make up Pool 3.
And in Leinster and La Rochelle's group, Premiership runners-up Sale Sharks and Leicester Tigers open proceedings against Stade Francais and DHL Stormers.
You can watch all the action on TNT Sports - the new name for BT Sport from Tuesday 18 July.