Travolta, Allen -- The Real "Skinny"

John Travolta strips down to his bathing suit during the filming of his latest flick -- and the results aren't pretty.

The star -- whose bod is far from his ripped self in "Staying Alive" more than 20 years ago -- was in New Mexico filming the aptly named "Wild Hogs," about a group of suburban biker wannabes.

In one scene, Travolta and co-stars William H. Macy, Tim Allen, and Martin Lawrence go skinny-dipping in a local watering hole, only to be confronted by a naked gay man who tries to entice them into a game of marco polo.

Travolta isn't the only member of the cast who looks like he could use a Bally's membership -- check out Allen and Lawrence.