Mercier left Gloucester in 2003

Mercier, 28, was Gloucester's leading points scorer between 2001 and 2003.

Gloucester director of rugby Nigel Melville said: "Ludo doesn't need any introduction here at Kingsholm, we're well aware of his ability."

Mercier, who is 13th in the all-time Zurich Premiership scoring list, has amassed 255 points during the current French season with four games to play.

Melville added: "It's great news and another piece of the plan confirmed for the 2005/06 season, following on from Mike Tindall, Patrice Collazo and Peter Richards, as well as some of the current players signing new contracts."