"They called me up and asked if I was interested," Federline, 31, tells PEOPLE. "I was up for a different part originally, but then they didn't want me playing myself. I think they thought it would be funnier for me as a Canadian border guard."
One day of shooting on location in Vancouver later, Federline was transformed, donning a hat, uniform and badge for his cameo in American Pie Presents: The Book of Love, out on DVD on Dec. 22.
Newly svelte from his appearance on Celebrity Fit Club, Federline is ready and available for more work. "If anybody has any more cameos – or actual roles they want to me in – that would be great," he says. – Mike Fleeman