CHRISTOPHER PLUMMER, FRANK LANGELLA AND BENJAMIN WALKER STAR IN THE HBO FILMS PRESENTATION "MUHAMMAD ALI'S GREATEST FIGHT," DIRECTED BY STEPHEN FREARS, DEBUTING OCT. 5

Famous for both his signature shuffle and verbal sparring, boxer Cassius Clay quickly rose to fame in the '60s, becoming the world's best-known athlete - and eventually its most controversial. After joining the Nation of Islam and adopting the name Muhammad Ali, he was widely denounced for refusing to be drafted into the U.S. military, based on his religious opposition to the Vietnam War. Stripped of his title and banned from the sport, the self-proclaimed "Greatest" lost nearly four years of his boxing prime to legal battles. In 1971, his case for being a conscientious objector eventually reached the United States Supreme Court, rooted by tradition and conservative ideals with Nixon-appointed Chief Justice Warren E. Burger at its helm.

HBO Films presents in association with SAF Films West MUHAMMAD ALI'S GREATEST FIGHT, starring Academy Award(R) winner Christopher Plummer ("Beginners"), Academy Award(R) nominee Frank Langella ("Frost/Nixon") and Benjamin Walker ("Abraham Lincoln: Vampire Hunter"); directed by Academy Award(R) nominee Stephen Frears ("The Queen") from a script by Shawn Slovo ("A World Apart"); and executive produced by Emmy(R) winner Frank Doelger (HBO's "Game of Thrones" and "The Gathering Storm"), Emmy(R) winner Tracey Scoffield (HBO's "The Gathering Storm"), Jonathan Cameron and Stephen Frears.

Debuting SATURDAY, OCT. 5 (8:00-9:40 p.m. ET/PT), exclusively on HBO, the film goes behind the closed doors of the United States Supreme Court as its nine justices - Chief Justice Warren E. Burger (Frank Langella), Hugo Black (Fritz Weaver), William O. Douglas (Harris Yulin), John Harlan II (Christopher Plummer), William Brennan, Jr. (Peter Gerety), Potter Stewart (Barry Levinson), Byron "Whizzer" White (John Bedford Lloyd), Thurgood Marshall (Danny Glover) and Harry Blackmun (Ed Begley, Jr.) - decide the outcome of Muhammad Ali's landmark appeal. Justice Harlan, a respected jurist with 15 years on the court, finds himself at odds with the status quo after his perspective is challenged by the contemporary ideals of his new clerk, Kevin Connolly (Benjamin Walker). The film explores the intricate politics behind these historic decisions in a time of rapid social and cultural transformation in the American landscape.

Other HBO playdates: Oct. 5 (2:15 a.m.), 6 (5:00 p.m.), 8 (1:00 p.m., 8:30 p.m.), 13 (10:30 a.m., 1:00 a.m.), 16 (11:45 a.m., 8:00 p.m.), 19 (3:45 p.m.), 22 (5:00 p.m., 12:30 a.m.), 24 (10:00 a.m., 8:30 p.m.), 26 (12:15 p.m.), 28 (10:15 a.m.) and 31 (5:00 p.m., 12:10 a.m.)

HBO2 playdates: Oct. 10 (10:00 a.m., 8:00 p.m.) and 20 (9:30 a.m., 8:00 p.m.)

ABOUT THE FILM

When executive producer Frank Doelger at Rainmark Films asked writer Shawn Slovo to develop a film version of some of the events portrayed in the book of the same name by Howard Bingham and Max Wallace, she was immediately attracted to the volatile time period in which the film is set.

"The late '60s, early '70s in American history is the most fascinating period," Slovo says. "It wasn't only that you had the cast of great characters and the great story, but also the context of the times. I seized on this opportunity when Frank gave it to me."

To bring the script to life, Slovo was paired with celebrated director Stephen Frears, whom she credits for attracting such top actors as Christopher Plummer and Frank Langella to the film. She notes, "People want to work with Stephen and for the obvious reasons. And that's a huge asset to this."

Slovo's script called for archival footage to portray Ali. Frears and the other filmmakers agreed with the decision not to cast an actor for the scenes showing the inimitable boxer, who was as bold and outspoken outside the ring as he was inside.

Slovo explains, "Any chance he got, Ali was talking about why he believed in what he believed, why he refused to fight. So we have this brilliant archive footage, and once you see it, you think, 'There is absolutely no point in trying to find an actor to play this man.'"

Despite the extensive amount of information gathered on the justices, the actors were also encouraged by Frears to trust the script and shape their parts from their insights. "The production sent me four books, and out of the four books, I got a paragraph of information on Warren Burger as a person," says Frank Langella. "There is very little personal information about these guys, and I think that's probably something the justices develop, which is not to have them be shining examples of personality, but to be men who stand for justice."

The clerks, as an ensemble, provide an emotional and youthful perspective to the justices, who strive to practice strictly by the law. Justice Harlan's fledgling clerk, Kevin Connolly (Benjamin Walker), struggles not only with his tradition-minded employers, but also with the established clerk system that favors Ivy League students. In the historical appeal of Ali's case, the clerks played an integral role in influencing the reversal of the justices' decision.

Shot in New York City, with additional locations in New York State, MUHAMMAD ALI'S GREATEST FIGHT went to great lengths to evoke Washington, D.C. in the 1970s.

"We had a difficult time finding neighborhoods in New York City that looked like, felt like, Georgetown, which is a lot older than most of the locations in New York," says production designer Dan Davis. "We stumbled across Schenectady and found this fantastic neighborhood that looked almost identical to Georgetown."

After extensive behind-the-scenes tours of the Supreme Court, the production meticulously built a central courtroom on a stage in Brooklyn, in addition to filming elsewhere in New York City for scenes of the justices' chambers and clerks' offices. Seasoned costume designer Molly Maginnis also came on board to recreate the fashions of the early '70s, working with robe manufacturer Bentley & Simon, which has outfitted many of the Supreme Court justices since 1918.

For more on the film, visit Facebook.com/HBO and Twitter @HBO #MuhammadAli.