Alun Wyn Jones has joined French club Toulon as cover during the World Cup.
The ex-Wales and British and Irish Lions captain has signed as a 'medical joker' for the tournament's duration.
The second row, 37, announced his shock international retirement in May as the most-capped player in world rugby.
Toulon director of rugby Pierre Mignoni said: "We are delighted and honoured to welcome a legendary player like Alun Wyn Jones to Toulon. His career demonstrates his immense talent."
He added: "His experience, his mental and physical strength as well as his leadership will add to the locker room and to his team-mates."
Jones has initially signed a short-term contract with the club to cover squad absences during the World Cup, a term known in France as a 'joker'.
The domestic Top 14 season kicks off mid-August, before resuming after the World Cup in the final week of October.
Jones brought an end to his 17-year career at the Ospreys in June having also announced his retirement from Test rugby just weeks after being named in Warren Gatland's preliminary World Cup squad.
He made his debut for Ospreys in 2005, having started his career a year earlier with Swansea, and went on to win three league titles.
Also captain of his country, the lock forward has played a world-record 170 international matches, with 158 games for Wales and 12 Tests for the Lions.
He is the latest in a long line of Welsh players to head to Stade Mayol where he will join former Ospreys team-mate Dan Biggar.