Kevin Federline Joins 'Celebrity Fit Club' With Ex Shar Jackson

Looks like Kevin Federline is tired of all the K-Overfed jokes, because TMZ has learned he officially signed on to do the next season of "Celebrity Fit Club."

Federline has packed on the pounds of late, but he's on a mission to reduce the rolls.

Earlier today, a TMZ employee watched Britney's ex saunter onto the Simi Valley, CA set of the VH1 weight-loss reality show.

PHOTOS: Click for TMZ's exclusive "K-Overfed" pics.

As TMZ first reported, Bobby Brown, Nicole Eggert and Kevin's other baby-mama Shar Jackson will also join him in trimming the fat.

Read more at TMZ: K-Fed Will Become K-Fit