Sherwin scored 155 points during his time with the Bulldogs

The 29-year-old, who was released by Australian side Canterbury Bulldogs despite having 12 months left on his contract, will replace Danny Brough.

Sherwin played 191 games in nine years for the Bulldogs and helped them win the NRL championship in 2004.

He said: "The Bulldogs have been my life but the offer from Castleford allows me to continue playing."

606: DEBATE How good a signing is Sherwin?

Bulldogs coach Steve Folkes said: "Although it is not standard practice for us to release players early from their contracts, this opportunity was in his best interests and we would not want to stand in his way."

Sherwin is Castleford's fifth recruit, joining Luke Dorn, Michael Korkidas and Mark Edmondson, who switched from relegated Salford, and Scott Moore, who is on a season-long loan from St Helens.