Bradley Cooper has the tightest, shortest shorts around. That's a fact. The Hollywood star was snapped shooting Clint Eastwood's American Sniper on Wednesday (4th June) sporting an incredible pair of khakis to get into character as America's deadliest sniper, Chris Kyle.

Cooper was also wearing a white T-shirt and combat boots as he shot a Navy SEAL training scene, doing press-ups while being sprayed with a water hose. 

The Oscar-nominee has reportedly been working out round the clock for the role and has gained 40 pounds of muscle. His co-star Eric Close told E! that Cooper is completely immersed in the role of Kyle. 

More: see pictures from the wedding scene in 'American Sniper'

"[Bradley] put on like 40 pounds. He's really been working hard. He looks great. He's really taken on this character.He really takes this story personally and wants to do an honorable job for Chris' memory and for his family."

Bradley CooperBradley Cooper shooting a funeral scene for 'American Sniper'

Kyle claimed to have 160 confirmed kills in his autobiography American Sniper: The Autobiography of the Most Lethal Sniper in U.S. Military History, though was killed himself when shot at a shooting range in Texas by a fellow veteran in 2013. The movie, a retelling of Kyle's life, is due in theaters next year and also stars Sienna Miller as Chris's wife Taya. 

In May 2013, it was announced that Steven Spielberg would direct the movie, though he dropped out shortly after. Clint Eastwood was hired as director in August and principal photographer and production began in Los Angeles in March. Some of the scenes will be shot in Morocco, though so far Cooper has been spotted filming in Santa Clarita, El Centro, Culver City and Marin del Rey. 

Clint EastwoodClint Eastwood on the set of 'American Sniper'