Jeremy Renner is stepping into the ring for a Rocky Marciano biopic.

The Hurt Locker star will play the famous boxer who held the heavyweight crown from 1952 to 1956 in "Undefeated: The Rocky Marciano Story."

Marciano is the only heavyweight champion to retire from his professional career undefeated, with a record of 49-0 - a record that Floyd Mayweather Jr. recently matched when he retired as world champion in September.

Morris S. Levy, who owns the rights to the life story, will produce the film. The project, written by Samuel Franco and Evan Kilgore, is currently seeking a director.

The film will follow Marciano's life from childhood until his death in a plane crash in 1969.

Renner, repped by CAA, Untitled and Felker Toczek, is known for playing superhero Hawkeye in the Avengers franchise and can be seen in the upcoming Marvel film Captain America: Civil War.