Munster have received a tough draw against reigning champions Saracens in next season's Champions Cup pool stages.
As well as a repeat clash against the team who knocked them out at the semi-final stage in 2017 and 2019, Munster will face Racing 92, who defeated them in the 2018 semi-final.
The French side will visit Thomond Park with former Munster stars Simon Zebo and Donnacha Ryan now part of their team.
Welsh side Ospreys complete a tough Pool 4.
"Racing, Saracens and Munster in the same Pool looks heavy," said Dimitri Yachvili, who made the draw with Bryan Habana in Lausanne, Switzerland.
“This Pool is full of top quality sides and it will be a massive challenge,” head coach Johann van Graan told munsterrugby.ie.
It’s such a tough draw but that’s why it’s called the Champions Cup and that’s why we want to be in this competition, it will be a very exciting challenge for us and it is one that we are looking forward to.
2019 runners-up Leinster are the top seeds in Pool 1, and they were drawn against Lyon, Northampton Saints, and Benetton.
“Today was the first day of pre-season for us in UCD so to now have the full Heineken Champions Cup draw confirmed, in addition to last week’s confirmed Guinness PRO14 conferences, it definitely sharpens the mind for the considerable task ahead this season," head coach Leo Cullen told leinsterrugby.ie.
“Overall it’s a very competitive pool but we very much look forward to the challenge that it presents in particular in a World Cup season.”
Connacht, on their return to the competition for the first time since the 2016-17 season, were drawn alongside Toulouse, Gloucester, and Montpellier in Pool 5.
Ulster find themselves in Pool 3 with Challenge Cup champions Clermont Auvergne, Harlequins and Bath.
Ronan O'Gara's first Champions Cup campaign as a head coach will see his La Rochelle side meet Exeter Chiefs, Glasgow Warriors, and Sale Sharks.
The tournament is set to kick-off on Friday, November 15 - a later start due to the World Cup - with the first four games played in the space of five weeks.
The final will take place at the Stade de Marseille on Saturday, May 23, 2020.
Champions Cup pools
Leinster Rugby, Lyon, Northampton Saints, Benetton Rugby
Exeter Chiefs, Glasgow Warriors, La Rochelle, Sale Sharks
ASM Clermont Auvergne, Ulster Rugby, Harlequins, Bath Rugby
Saracens, Munster Rugby, Racing 92, Ospreys
Toulouse, Gloucester Rugby, Connacht Rugby, Montpellier
Challenge Cup pools
Castres Olympique, Worcester Warriors, Dragons, Enisei-STM
Scarlets, RC Toulon, London Irish, Bayonne
Wasps, Edinburgh Rugby, Bordeaux-Bègles, Agen
Stade Français Paris, Bristol Bears, Zebre Rugby Club, Brive
Cardiff Blues, Leicester Tigers, Pau, Rugby Calvisano