BRITNEY SPEARS' ex-chubby...oops, hubby, KEVIN FEDERLINE has signed up to shed pounds on U.S. TV as part of the cast of the new season of reality show CELEBRITY FIT CLUB.

The heavyweight former dancer will join his ex-girlfriend Shar Jackson and Bobby Brown on the bootcamp weightloss show.

K-Fed was spotted visiting the Simi Valley, California set of the show on Tuesday, according to TMZ.com.