Director of Football Steve Simms said: “Ashley is an experienced Super League player who can play a number of positions and he’s a fast outside back.
“He’s played for England and he’s going to give us some great options in our back line. We are looking forward to him being a big part of our 2010 season.”
Gibson played his junior rugby at Stanningley before joining Leeds. He has made 32 appearances for the club scoring 13 tries, although he missed most of the 2007 season after rupturing his anterior cruciate ligament.