The European Champions Cup has been expanded to include 24 teams and the 2020-21 Challenge Cup format has also been altered due to the coronavirus pandemic.
European Professional Club Rugby (EPCR) on Wednesday announced that there will be an additional four clubs in Europe's premier club competition, with home and away quarter-finals played for the first time.
There will be two pools of 12 teams - eight apiece from the Premiership, Pro14 and Top 14 - and four rounds of matches, with no teams from the same league coming up against each other in the group stage.
The changes for the competition, which ends with a final in Marseille on May 22, have been made on an exceptional basis amid the backdrop of the COVID-19 crisis.
Fourteen clubs will compete in the Challenge Cup - six from the Top 14, four from the Premiership and four Pro14 sides - and play four rounds of matches in a single pool, again not facing teams from their own country.
There will be a round of 16 before the quarter-finals and the final will take place in Marseille on May 21.
We're delighted to announce a hugely exciting, exceptional format for the 2020/21 Heineken Champions Cup!— Heineken Champions Cup (@ChampionsCup) September 2, 2020
Check out our video to make sure you're up to speed with how it's all going to work pic.twitter.com/gTLQvh4WMQ
EPCR chairman Simon Halliday said: "With an expanded knockout stage and no repeats of domestic matches during the pool stage, this format creates brand new competitive opportunities for Europe's elite clubs and their fans.
"In this time of change, the Champions Cup with its global stars of the game, its passionate supporters and its unique match-day atmosphere undoubtedly remains The One to Win."