Run, K-Fed, run!

On Monday's Celebrity Fit Club finale, Kevin Federline celebrates his new physique by taking a "fat run."

"You were a fat a--," Fit Club's Harvey Walden tells the dancer-rapper, 31, as he hands him 28 lbs. of fat to indicate the amount of weight he dropped during his nine weeks on the show.

After seeing the lard, Federline (who had a starting weight of 232 lbs.) vows: "There's no way I'll ever, ever go back to that!"

Watch VH1's Celebrity Fit Club: Boot Camp finale Monday at 9 p.m./ET to see the transformations of Federline's cast mates including his ex Shar Jackson, Bobby Brown and Project Runway's Jay McCarroll.