Thompson, who spent last year at Oldham, follows coach Tony Benson down south, and is their fifth signing for 2013 – following the captures of Dave Ellison, Valu Bentley, Andrew Hoggins and Oliver Johnson.
Benson said: “He is a very strong player who scores a lot of tries and can also play six. He’s very skilful with the ball in hand and is a very consistent player.”
Thompson made one appearance for the Wolves, scoring a try in the 44-34 win over Harlequins in September 2009.
He said: “I had a number of other offers but I spoke with Tony and I was really impressed with the set up of the club, the board members, players which were signing and after having a look around the ground decided this was the place to be.”