Bradley Cooper has become the latest Hollywood actor to completely reinvent his body to fit a role. 

The 39-year-old has been hitting the gym and packing on the pounds in an effort to accurately portray the physicality of the late Navy SEAL Chris Kyle. Director Clint Eastwood is adapting Kyle's best-selling book "American Sniper: The Autobiography of the Most Lethal Sniper in U.S. Military History," in which he recounts how he achieved his unofficial status as the most lethal sniper in American history. Cooper snagged the rights to book for this production company 22nd & Indiana in 2012, less than a year before Kyle was tragically killed at a shooting range by a fellow veteran.

Actor Eric Close, who stars with Cooper in the film, says the actor has committed himself fully to honoring Kyle and his family. 

“He’s 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,” Close told E.

Back when Cooper was doing the media rounds for his 2010 film "The A-Team," he revealed that his body transformations are pulled off with time in the gym and eliminating sugar, salt and flour. 

"I shrunk back down two weeks after we finished shooting," he said. "It was depressing . . . I was craving pizza so badly that the night we finished shooting I ate two arugula and prosciutto pies and a plate of Cherry Garcia ice cream with trail mix on top of it. And I did it again the next night."

"American Sniper" is due for release in 2015.

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