Oprah Winfrey feels ''intimidated'' by her acting roles.

The 63-year-old star is best-known as a talk show host, but Oprah has admitted acting was her first love and revealed that her starring role in the Steven Spielberg-directed adaptation of the novel 'The Color Purple' in 1985 was the fulfilment of a deep-rooted ambition.

Oprah shared: ''You know, I always wanted to be an actress.

''I never wanted anything more in my life than I wanted to be in 'The Color Purple', and have never allowed myself to want anything as much again.''

Oprah was desperate to appear in the movie base of her love of Alice Walker's novel.

She told Variety: ''The first time I read that book, I went and got eight more copies for everybody else I knew to read that book. This is before I even had the idea for a book club.

''I told everyone in the world, 'I want to be in that movie. I'll carry water for Steven Spielberg. I'll hold a script. I'll do anything.'''

Oprah's performance in the movie, in which she played the part of Sofia, was widely lauded by critics - but the American star harboured doubts about the role.

She explained: ''I didn't feel that I was [worth it]. By the time I actually auditioned for it, I knew there is a God. Because I literally called that in.''

The media mogul recently returned to acting in the adaptation of 'A Wrinkle In Time', which is directed by Ava DuVernay.

And during a conversation with her award-winning co-star Reese Witherspoon, Oprah admitted to being intimidated by the experience.

She recalled: ''I just finished doing 'A Wrinkle in Time' and I asked Reese, 'How many movies have you done?' And she said, 'Oh, hundreds. Hundreds.' And I was thinking, 'I think I've done five. I hope she never asks me how many I've done.'

''And I always feel a bit intimidated where you're literally taking on the life of someone else.''