Watch Bradley Cooper In Tense New 'American Sniper' Trailer
Hunky actor gained 40 pounds for the role of Chris Kyle in the Clint Eastwood-directed flick...
Cooper plays Navy SEAL Chris Kyle in the Clint Eastwood-directed movie, which tells the story of Kyle's time in Iraq and his mission to protect his fellow soldiers.
The flick - which also stars Sienna Miller - saw Bradley gain 40 pounds of muscle in order to portray Kyle, with the hunky actor also training with real-life SEAL teams - including those who had worked alongside Kyle.
Kylie was shot dead in February 2013, with Cooper recently telling USA Today: "I had to do right by him and his family, there was really no choice.
"Knowing that they are putting all of their stories in your hands and the responsibility of that, it’s actually unique."
Before his passing, Kyle confessed in his autobiography that he was responsible for 160 kills during his career, with Bradley saying: "I remember getting a chill through my body realising what he had to do.
"Thank God I got to talk to him once on the phone. It was a very quick conversation. But I did tell him how serious I was about making this movie."
He added: "And he should just know that whatever fears he had about Hollywood, to just put them aside and trust me. That I was going to do everything I could to tell this story."
American Sniper hits UK cinemas on 16th January, 2015.