Wales scrum-half Rhys Webb will leave Ospreys at the end of the season to join Toulon on a three-year contract.
Webb, 28, is out of contract next summer with the Welsh Rugby Union and Ospreys.
The move could jeopardise his international future, as WRU selection policy permits only four players at clubs outside Wales to play for the national side for the next two seasons.
The quota will drop to just two wildcard picks for the 2019-20 season.
Webb's Wales and Ospreys half-back partner Dan Biggar will join English side Northampton next season.
The news of another star's departure will be a blow to Welsh rugby, with Webb to end his 11-year association with the region.
He made his debut for Ospreys in 2007 after coming through the Bridgend ranks and played his first game for Wales in the 2012 Six Nations against Italy as a replacement.
Webb, won two British and Irish Lions caps on the 2017 tour to New Zealand, has 28 Wales caps and scored a try off the bench for the Lions in the first Test defeat against New Zealand in June.
Toulon have previously recruited Wales duo Leigh Halfpenny and Gethin Jenkins.
Source: BBC Rugby Union News