Will Smith didn't pull any punches in his portrayal of Muhammad Ali in Ali (opening Christmas Day). Beyond the challenge of capturing the man and the myth, Smith had to look convincing in the ring.

"I was sparring with former heavyweight champ Michael Bent and I told him not to be afraid to hit me," he recalls to TV Guide Online. "So he landed a punch right in the middle of my head and it sort of compressed down into my shoulders. I felt an electric shock from the base of my neck to the back of both elbows. But I didn't fall down. And that's when something almost animalistic took over, like a catharsis. You think, 'I can do this.'

"That's the day I felt like a fighter," he adds, "because I could take it and give it back."

Smith also got into a tussle with The Greatest himself — albeit a verbal one. "I first met Ali a few years ago when I was trying to decide whether I could do justice to the role," he explains. "The champ looked at me and said, 'I guess you'll be OK. You're almost pretty enough to play me.' After I started doing the film, he kept teasing me that way. Finally, one day I looked at him and said, 'You know what? Everybody is telling me that I'm too pretty to play you.' Fortunately, he thought it was funny."

Come Oscar night, Smith may be the one in a giddy mood if buzz about his Ali performance is any indication. But the 33-year-old former sitcom star admits that his experience working on the Michael Mann-directed biopic has already made him a winner. "First, it was being forced to go that extra mile, that extra step and to work a little bit harder for Michael," he says. "Then, it was my first trip to Africa where we filmed and meeting Nelson Mandela and a lot of ordinary people I'll never forget.

"You can't go through that experience and not understand the definition of greatness," he concludes. "I don't know whether I can ever achieve it, but I understand what it takes to get there."