Fifty Shades of Grey star Luke Grimes is in final negotiations to join the cast of American Sniper, which includes Bradley Cooper, Sienna Miller and Jake McDorman.

This drama is adapted from the book of the same name by Navy SEAL Chris Kyle, which recounts his journey from working as a rodeo cowboy to becoming the deadliest sniper in U.S. military history, with over 150 confirmed kills. Luke Grimes is playing fellow SEAL team member Marc Lee, although no further character details were given.

Clint Eastwood is directing from an adapted screenplay by Jason Dean Hall (Paranoia, Spread), with Bradley Cooper, Andrew Lazar, Robert Lorenz and Peter Morgan producing. It isn't known when production will begin.

RELATED: BOX OFFICE: American Sniper Wins Again with $64.3M

Aside from playing Christian Grey's brother Elliot in the upcoming Fifty Shades of Grey, Luke Grimes recently starred in All the Boys Love Mandy Lane and Taken 2. He also appeared in a six-episode arc as James on the HBO series True Blood.