Hollywood Ali: Will Smith tries to pack a punch embodying the greatest, and most controversial, fighter ever. (arts).

HE FOREVER BLURRED THE LINES BETWEEN SPORTS, politics, and culture. In the ring, boxer Cassius Clay won an Olympic gold medal in 1960 and the world heavyweight title in 1964. Within 10 years, Clay met Black Muslim activist Malcom X, converted to Islam himself, changed his name to Muhammad Ali, defied the draft at the height of the Vietnam War for religious reasons, was stripped of his title for it, and won it back.

The saga of the fighter called "The Greatest" comes to the big screen with the December 25 release of the movie Ali, starring Will Smith. "Is it going to be controversial?" asks screenwriter Eric Roth. "Are you kidding? It's about Muhammad Ali. Do you really think all the things he stood for don't matter anymore? His name is still a lightning rod for hot-button issues in American society."

Director Michael Mann aims to stay true to Ali, a man forged by race, religion, strength, and showmanship. "We show him at his best, defying the U.S. government, refusing to be inducted into the Army, and losing three-and-a-half years of his career for it," he says. "We also show him at his worst, taunting and insulting his black opponents and cheating on his wife. This isn't an idealized Ali."

The daunting subject matter and the potential for controversy kept the idea of a movie about Ali kicking back and forth for more than a decade. Mann--who tackled the deceptive practices of big tobacco in directing the fact-based 1999 movie The Insider--took on the project. What he had agreed to was a film about an icon who, according to the Guinness Book of World Records, had passed Abraham Lincoln and Jesus Christ to become the most written-about human being in the world's books and periodicals.

Still, the movie almost didn't get made. Last fall, Sony Pictures, worried about the budget, actually pulled the plug for a brief time while Mann and Smith scrambled to get the costs down; both believed in the project enough to assume partial responsibility for costs.

But Smith's main responsibility is in front of the camera, to shed his rap-lite, funnyman image and capture the essence of Ali. "The pressure is on Will," Mann says, "because he has to convince you right out of the locker room, bam, first impression."

Wisely, Smith didn't see his job as an impersonation. "What I'm trying to do is an interpretation of the man on the inside that motivated the one the world saw," he says. "I'm not going to say I look like Ali, though the way I'm done up, people tell me there's a resemblance. But I do think I can get him from the inside, suggest his motivations, his passions, what he was about. I think I can create a character a lot like Muhammad Ali."

For Smith to sell himself as Ali, he had to go to boxing school. He beefed up to about 215 pounds, Ali's usual fighting weight, and worked for months with former boxer and master trainer Darryl Foster. "The first thing he said to me was, `You're going to know what it feels like to be a fighter before this is through. You're going to know what it's like to get hit,'" Smith recalls. "I thought, `Uh oh, here's where we start paying dues.'"

The hardest aspect to capture, though, was Ali's voice--part preacher's, part political leader's, part pro wrestler's. "People won't forgive me if I don't sound like him, the rhythm, the tone, the cadence," Smith says. He spent days studying films of Ali, from early Olympic footage to famed interviews with sportscaster Howard Cosell.

The actor playing Cosell, Jon Voight, says Smith is doing something no one has pulled off before, not even the champ. "It's such a big role, Ali himself couldn't play it," Voight says, referring to a highly idealized, little seen 1977 film called The Greatest, in which Ali played Ali.

Smith's toughest potential critic has had no recorded comment. In Miami in May, the real Muhammad Ali slipped onto one of the movie's sets, a re-creation of the city's legendary Fifth Street gym. The scene being filmed involved Ali and his reconciliation with his friend Drew "Bundini" Brown, played by Jamie Foxx. At the end, Ali's famous battle cry of "float like a butterfly, sting like a bee" broke out. The 59-year-old Ali, his hands shaking from the Parkinson's disease that is ravaging his body, smiled and nodded but made no comment. "Man, Muhammad Ali was watching me," Smith said, then shook his head. "I hope I was good."