The first trailer for the true-life story of Clint Eastwood's "American Sniper" has been shared and the tension-filled first glimpse of Bradley Cooper in character has everyone on the edge of their seats.

Cooper stars as Chris Kyle, a Navy SEAL sniper who held the record for highest number of sniper kills in American history.

Kyle's autobiography, "American Sniper: The Autobiography of the Most Lethal Sniper in U.S. Military History," formed the basis for the film. Kyle served four tours in the Iraq War and was later killed at a shooting range by a fellow military veteran in February 2013.

Cooper was able to speak to Kyle once before he was killed, when he first secured filming rights to the sniper's story.

"Thank God I got to talk to him once on the phone," Cooper told USA Today. "It was a very quick conversation. But I did tell him how serious I was about making this movie. 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."

After his death, Cooper felt obligated to complete the project for Kyle's family. Included in the cast is actress Sienna Miller, who plays Kyle's wife, Taya Renae, and is featured heavily in the film.

"I had to do right by him and his family, there was really no choice," Cooper said. "You're sitting across the dining-room table talking to this person's father and mother. And his children and wife are there. And he's passed away. Knowing that they are putting all of their stories in your hands and the responsibly of that, it's actually unique."

Cooper serves as a producer as well to the Clint Eastwood-directed film. Warner Bros. and Village Roadshow are financing the picture, which was adapted by screenwriter Jason Hall. "American Sniper" is expected to reach select theaters on Christmas Day and expand nationwide Jan. 16.