The Welsh Rugby Union will hold a trial for the first time in 14 years ahead of next month's two-Test South Africa tour.
Rob Howley will coach the Probables, with his fellow Wales assistant Robin McBryde in charge of the Possibles for a game that will take place at Swansea's Liberty Stadium on May 30th.
Wales head coach Warren Gatland will then announce a 31-man South Africa tour squad.
Wales will face South Africa in Durban on June 14th, and then Nelspruit seven days later.
Gatland says the trial will enable them to work with the extended squad and see those players in our environment as preparations ramp up for next year's World Cup.