Smith out to prove doubters wrong

Will Smith has revealed how he was told to avoid playing the heavyweight role of Muhammad Ali - a part which has earned him an Oscar nomination.

The 33-year-old actor was taking time out ahead of the Australian premiere of Ali, his latest film.

Smith said that people close to him suggested taking on the role of the larger-than-life Ali in the film directed by Michael Mann would be a mistake.

"There's a wonderful delusional quality I possess that allows me to attempt things that are really bad ideas," Smith said ahead of the film's Australian release. "Two years later, I'm sitting in Australia and I'm an Oscar nominee."