Sam Rockwell is to play former US President George W. Bush in Adam McKay's upcoming Dick Cheney biopic.

According to The Hollywood Reporter, the 48-year-old actor is in final negotiations to add his name to the already impressive cast.

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.

Christian Bale is portraying Republican politician Cheney - who was the 46th Vice President of the United States from 2001 to 2009 - whilst Steve Carell, Amy Adams and Bill Pullman are also attached to the project.

Carell is playing Donald Rumsfeld, the Secretary of Defence under President Bush whom Cheney served under, with Adams being lined up to star as the Vice President's wife Lynne Cheney.

McKay's movie is set to follow Cheney from when he avoided military service in the Vietnam War, his rise to CEO of the multinational corporation Halliburton and finally becoming one of the most powerful and influential vice president's to ever hold office and his actions which led America into the Iraq War in the wake of the 9/11 terrorist attack.

The script is now complete following moths of research and shooting is due to start in September.

McKay is producing the film for Paramount alongside Will Ferrell and Kevin Messick from his Gary Sanchez Productions. Brad Pitt's Plan B Entertainment is also taking on producing duties.

As well as his impressive political career many will remember Cheney for accidentally shooting Texas attorney Harry Whittington during a hunting trip.