The actor has gained weight for new role

Bradley Cooper has been spotted in a pair of eye-wateringly tight shorts on the set of his latest film.

The muscly actor, 39, showed off his rather shapely bum in the tiny beige kecks as he hung about during filming of American Sniper in Los Angeles this week.

Bradley – who has visibly bulked up for the role of Navy SEAL Chris Kyle in the flick – teamed the hot pants with a fitted white T-shirt and black boots.

After appearing to check his lines Bradley got on the floor for a particularly gruelling scene.

The Hangover star was seen doing exercises before being dosed with water by a commander as other men worked out around him.

It’s thought that Bradley – who is dating British model Suki Waterhouse – has gained 40lbs for the very physical role.

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Anna Francis