Castres - South African flank Pedrie Wannenburg has signed a two-year deal with Castres, the Top 14 club announced on Thursday.
The 31-year-old Wannenburg, formerly of Blue Bulls, was in the Ulster side which recently lost in the final of the European Cup to fellow Irish side Leinster.
Wannenburg joined Ulster in 2010 from South African side Bulls.
He will join compatriots Rory Kockott, Jan Bornman, Michael Coetzee and Antonie Claassen, who has recently signed from Brive, at the south-west side.