Sam Rockwell to Play George W. Bush in Adam McKay's Dick Cheney Biopic (Exclusive)

Christian Bale is portraying Cheney in the Annapurna production.

Sam Rockwell is joining Christian Bale in Cheney, Adam McKay’s biopic of former vice president Dick Cheney.

Rockwell is in final negotiations to add his name to the call sheet that already includes Steve Carell, Amy Adams and Bill Pullman for the drama from Annapurna.

Bale is portraying the titular character in a story that chronicles Cheney avoiding military service in the Vietnam War, his rise to CEO of the multinational corporation Halliburton and finally becoming what some have called the most powerful U.S. vice president ever to hold office.

Carell has been cast as Secretary of Defense Donald Rumsfeld, while Adams is playing Cheney’s wife, Lynne.

Rockwell will play Cheney’s boss, President George W. Bush, who steered the nation through the attacks of 9/11, the events that allowed Cheney to exercise his power when it came to fighting terrorism.

The project is aiming for a production start in September.

Producing are McKay and his Gary Sanchez Productions partners Will Ferrell and Kevin Messick. Brad Pitt and Dede Garner are also producing via their Plan B label.

Rockwell is gearing up for the Venice Film Festival premiere of Three Billboards Outside Ebbing, Missouri, the new comedic thriller from Martin McDonagh that also stars Frances McDormand and Woody Harrelson.

The actor recently wrapped shooting the Western drama Woman Walks Ahead with Jessica Chastain and is currently shooting the true-life period race drama The Best of Enemies with Taraji P. Henson.

Rockwell is repped by Gersh and Untitled Entertainment.