Joe Worsley, a World Cup winner with England in 2003, has joined Castres as defence coach until the end of the season, the Top 14 team announced on Monday.
Worsley, who won 78 caps in the back row for England and made five appearances for the British and Irish Lions, was on the coaching staff at Bordeaux-Begles from 2012 to 2019.
The 42-year-old also worked as a technical consultant for Georgia during the recent World Cup in Japan.