The "Mad Men" star has been cast as the military leader-turned-US president in Churchill, opposite "The Bourne Identity" actor Brian Cox as the titular British wartime Prime Minister, said the Hollywood Reporter.
The movie will centre around Churchill's leadership in the tense period leading up to the Allied Forces' D-Day landings in Normandy, France in 1944, during World War II, and also detail his relationship with his wife, Clementine, who supported him throughout the stressful time.
"Damage" actress Miranda Richardson has been tapped to play Clementine, while Suki Waterhouse and Julian Wadham round out the main cast.
Production is set to begin in May.