Mike Phillips and James Hook will be able to team up with Wales ahead of the Barbarians and Australia matches after they were freed by their French clubs.
Caretaker coach Rob Howley named Bayonne scrum-half Phillips and Perpignan fly-half Hook in a 38-man training squad for the Six Nations champions' summer itinerary, which includes a June 2 meeting with the Baa-Baas and three Tests Down Under.
The squad are set to meet up on May 21, with the exception of the Ospreys' contingent who will be preparing for the RaboDirect Pro 12 final against Leinster.
However Bayonne and Perpignan were not obligated to release Phillips and Hook as the date falls outside the International Rugby Board's agreement for the summer Tests.
The Welsh Rugby Union, though, have been notified that the players will be available for the start of the training schedule - and Howley praised the move by the French federation.
Howley said: "This is fantastic news for us as it means Mike and James will be fully involved in the complete preparation programme we have in place.
"They are both experienced international players but it is still a huge advantage to have them working within our environment from day one.
"We are extremely grateful to the French Rugby Union and the individual clubs involved for taking this step.
"It is a gesture which will undoubtedly benefit the players and I know they will want to thank their individual clubs for helping them fulfil their international commitments with Wales.
"It is an example of northern hemisphere rugby working in unity for the benefit of our players and the game in general.
"We are all aware of the difficulties we can encounter when Welsh qualified players are based outside Wales, but this decision shows there are opportunities for us to realise mutual benefits."
Clermont Auvergne full-back Lee Byrne was not included in Howley's squad as he is likely to be in action for his club up until the tour party leaves for three Tests in Australia.