But it seems that even Oprah Winfrey, 59, has her moments of doubt.
The talk show powerhouse has admitted her nerves over returning to the big screen after a fifteen year hiatus for the new movie Lee Daniels' The Butler.
Nervous: Oprah has admitted she was scared to return to acting after the flop of her last film Beloved in 1998
'It did scare me very much,' Oprah told the NY Daily News.
'I said to [director Lee Daniels], ‘I just don’t want to embarrass myself.’
Oprah was last seen in cinemas starring in the 1998 film Beloved, adapted from the much-loved novel by Toni Morrison.
Movie magic: In the film, Oprah plays Gloria the wife of Forest Whitaker's character Cecil Gaines who gets a job as a butler in The White House
It was a project that Oprah had tried to get made for ten years before it was finally released, and subsequently flopped at the cinemas.
The film opened with $8million in ticket sales and went on to earn a dismal $22million.
'I remember sitting at home the Saturday after it opened, and being told, "We’ve lost."'
Star turn: Oprah was nominated for an Oscar for her role in the Steven Spielberg film The Color Purple in 1985
Oprah revealed that she 'mourned' the loss of the film and thought she was depressed, which understandably made her concerned about returning to acting work again.
It was certainly not the same success she enjoyed in Steven Spielberg's The Color Purple - in which she was nominated for an Oscar.
Oprah, who has set up her own TV netwrok OWN, plays Gloria in the film the wife of Forest Whitaker's character Cecil Gaines.
The film tells the story of Cecil witnessing the great civil rights movement as he gets a job as a butler in The White House.
Oprah recently revealed that she was faced with a 'racist' shop assistant after she was refused to be shown a $38k handbag because 'it is too expensive for her'.
Oprah said: ‘I was in Zurich the other day, in a store whose name I will not mention. I didn’t have my eyelashes on, but I was in full Oprah Winfrey gear.
'I had my little Donna Karan skirt and my little sandals. But obviously The Oprah Winfrey Show is not shown in Zurich.
‘I go into a store and I say to the woman ‘‘Excuse me, could I see the bag right above your head?” and she says to me “No. It’s too expensive.”’
Oprah asked a second time to see the bag, which was locked in a cabinet to deter shoplifters.
Instead of making a scene, the billionaire TV magnate calmly left the Swiss store, but later hit back claiming she was the victim of 'racism'.
Owning it: Despite her nerves about acting, Oprah is won of the most successful and richest women in America