At first, Will Smith wanted nothing to do with the film "Ali."

"I didn't want to be the dude that messed up the Muhammad Ali story," Smith said in an interview with Time magazine, on newsstands Monday. But Ali, 59, said he was pleased with Smith's performance in the biopic opening Christmas Day.

"He's the only guy in the world who can look like me and act like me," Ali said.

Smith said one hurdle was relating to a man whose life had been so defined by racial injustice.

"I'm a child of rap music," Smith said. "We've got Bentleys. We can't even relate to not being able to sit at somebody's lunch counter. I'll buy the counter and throw you out."

Smith added 30 pounds of muscle to transform his body into a nearly perfect replica of Ali's, learned to box and studied Ali's Islamic faith to prepare for the role.

"For an African-American, Muhammad Ali is the biggest role you could have," Smith said. "Malcolm X, Muhammad Ali and Nelson Mandela — with any of those roles comes a responsibility."