Will Smith doesn't think he is "man enough" to play Nelson Mandela in a movie

Will Smith doesn't think he is "man enough" to play Nelson Mandela in a movie.

The 40-year-old actor - who previously portrayed Muhammad Ali in 2001 movie 'Ali' - has been touted to portray the history-making former South African President on the big screen but is worried he wouldn't be able to do the part justice.

Revealing he is also keen to play soul singer Marvin Gaye in a film, Will added: "I'm not certain I'm actor enough yet. I love both of those, and I need to make sure I'm man enough."

Will - who can next be seen in upcoming drama 'Seven Pounds' - also revealed despite starring in action blockbusters including 'Hancock' and 'I Am Legend', he prefers appearing in films which "push" his acting ability.

He said: "I have to challenge myself and push myself. My only job is to make sure I don't leave anything on the table, that I maximize what a young dude from Philadelphia can do in the world of cinema. There's no telling what I can create at this point."