Christopher Plummer, who could walk away with the first Oscar of his long career in just a few weeks, has closed a deal to star in HBO Films’ Muhammad Ali’s Greatest Fight, which is being directed by Stephen Frears.

According to Hollywood Reporter, Frank Langella also is coming on board the movie, which details the legal fight between Ali and the U.S. government when the fighter became a conscientious objector to the Vietnam War.

Ali was drafted into the Army in 1966 but declined to serve, citing his belief that the war was against the teachings of the Koran. When he appeared at an armed services induction in 1967 and refused to step forward when his name was called, he was arrested.

After being found guilty, a series of appeals were fought and the case wound its way up to the U.S. Supreme Court in 1971 (Clay v United States). Ali persevered, mainly due to the prevailing anti-Vietnam winds, and also managed to throw out provocative lines into the mainstream such as “I ain't got no quarrel with the Vietcong. No Vietcong ever called me N-----.”

Shawn Slovo wrote the script. Frank Doelger, Tracey Scoffield, Jonathan Cameron and Frears are exec producing the movie, which is still searching for its Ali.

Plummer, in his first deal since being nominated for an Oscar for his work in Beginners, will portray Supreme Court Associate Justice John Marshall Harlan II. Langella will portray Chief JusticeWarren Burger.

Plummer, repped by ICM and Lou Pitt of the Pitt Group, is currently on screen with The Girl with the Dragon Tatoo.

Langella, who received an Oscar nomination for his performance in Frost/Nixon, starred in Robot and Frank, one of the highlights of the recent Sundance Film Festival. He is repped by ICM.