Sides from the Championship will join Premiership sides in a revamped Premiership Rugby Cup next season.
The 24 teams in the top two tiers will be split into four pools of six with five group matches, followed by semi-finals featuring each pool winner in February 2024 and a final in March.
It is the first time in 18 years that Premiership sides will face lower-tier teams in a cup competition.
Exeter are the holders after beating London Irish in last month’s final.
The group stages will take place over five consecutive weekends from early September until early October, before the World Cup.
The news comes as Championship sides continue to have concerns over their level of funding from the Rugby Football Union and struggle to gain promotion to the top flight.
Ealing were ineligible for promotion because their ground did not meet Premiership criteria.
They lost at Jersey Reds on Saturday, with the island side now favourites to take the title having got a two-point lead with one game to go – their 4,000 capacity ground at St Peter is also deemed unfit for top-flight rugby.
It will also allow Wasps a chance to face Premiership sides next season – they will start life in the Championship next autumn after being removed from the top flight for financial reasons earlier this season.
“The new cup format is the result of great collaboration between the Championship, RFU and Premiership Rugby,” said Steve Lloyd, chair of the Championship Clubs Committee.
“The clubs are delighted with the opportunity a different format brings as well as the experience of playing Premiership sides and the opportunity to welcome new fans into our clubs and grow our audiences.”
Premiership Rugby’s rugby director Phil Winstanley added: “The Championship performs a crucial role within the English game and we’re looking forward to renewing some rivalries of old.
“It is many years since the Premiership and Championship clubs clashed in a cup competition.
“With the Rugby World Cup taking place in France, this competition will no doubt provide the best, young English talent with an opportunity to stake a claim in squads before the start of the Gallagher Premiership campaign.”
