Bradley Cooper arrives at the BAFTA awards ceremony in London
Bradley Cooper arrives at the British Academy of Film and Arts (BAFTA) awards ceremony at the Royal Opera House in London February 16, 2014. REUTERS/Luke MacGregor

Bradley Cooper, the "American Hustle" actor, may have recently gained weight. But he is still as fit as before even with his 40 pounds added weight.

Apparently, a new report said the weight gain is for the upcoming Clint Eastwood's movie "American Sniper," wherein the 39-year-old actor is playing the role of a Navy Seal named Chris Kyle.

"He put on like 40 pounds," Eric Close, Cooper's co-star in the movie playing a defense intelligence agent, shared to E! Online. Close also told the Web site that Cooper has been working hard.

"He looks great," Close said pertaining to Cooper. "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."

The American Sniper movie is based on the real life story of Christopher Scott "Chris" Kyle, a Navy Seal who according to his written autobiography was the "most lethal sniper" in the history of American military.

Kyle, apparently, held the U.S. record with 160 "confirmed" kills out of all the 250 "claimed" kills.

"American Sniper: The Autobiography of the Most Lethal Sniper in U.S. Military History" was Kyle's autobiography written with the help of Scott McEwen and Jim DeFelice which had nearly four thousand reviews on Amazon with an average of 4.5 out of 5 stars rating given by the reviewers.

Kyle has also written another book titled, "American Gun: A History of the U.S. in Ten Fire Arms" with writer William Doyle.

Considered to be a no.1 New York Times Best-Selling book, Kyle's autobiography has gained a reputation that apparently could be given justice by Bradley Cooper as he was chosen for the lead role.

The autobiography has also caught the filmmakers' attention. The Web still lists Steven Spielberg as the director of the movie, as of press time. Type American Sniper on the Google search engine and Spielberg's name will appear as the listed director of the movie.

According to an article on contactmusic.com, initially there have been rumors Spielberg and David O. Russell were interested in directing the movie. But the two-time Oscar-winning Director Clint Eastwood has gotten the job to direct with Bradley Cooper as the lead character.