Gloucester have secured home advantage in the first play-off fixture to secure a European Champions Cup spot next season.
Gloucester confirmed their place as England's representatives to contest the 20th and final qualifying berth by lifting the European Challenge Cup with victory over Edinburgh in last Friday's final.
After winning the toss for home advantage, Gloucester's Kingsholm will host the May 24 play-off encounter against the highest-placed Guinness PRO12 club that has not already secured automatic Champions Cup qualification, tournament organisers announced.
The winners will then meet the French Top 14's seventh-placed finishers on May 31 to complete the 2015-16 Champions Cup line-up.
If they win the opening play-off, Gloucester will again have home advantage - but at Worcester's Sixways Stadium, rather than Kingsholm, as Kingsholm is staging a Madness pop concert the previous day.
"We are delighted to have won the toss to stage the first fixture, and now look forward to seeing who we will meet in that game," Gloucester chief executive Stephen Vaughan told the club's official website.
"Should we win that match, and no-one is taking anything for granted, we have had to make contingency plans for the second play-off game, and that contingency would be for us to play at Sixways Stadium in Worcester.
"When we finalised our concert schedule for the summer, there was no prospect of a play-off fixture on this weekend, and the clash, while unfortunate, is unavoidable.
"Based on the information at hand at the time and historic dates for European games, it was the correct thing to do for the club at that point in time.
"We have looked into various options for the second play-off game should we qualify, and decided, after due consideration, that playing the game at Worcester would be the best option. We are very grateful to Worcester Warriors for potentially accommodating us."