Julia Roberts has compared acting on stage to childbirth.

The 'Mirror Mirror' star made her Broadway debut in 'Three Days of Rain' in 2006 and although she has plans to return to the theatre, the actress - who has three children, twins Hazel and Phinnaeus, seven and Henry, four, with husband Danny Moder - admitted it wasn't the easiest experience ever.

She said: "It's like childbirth, you don't know until you've done it but you get a little bit away from it and you go, 'Of course I want to do that again'. You get sucked back into doing theatre because it's really thrilling and does challenge you as an actor in really unique ways. You know, I love the medium of film, I love that environment but it's just different."

Julia also believes she would enjoy the experience more this time around.

She told the new issue of Vanity Fair magazine: "I really enjoyed doing 'Three Days of Rain' but I could definitely find ways to have more fun because now I have a much better sense of what I'm getting into. I mean when we did 'Three Days of Rain', I had two little children and was doing eight shows a week. There was a relentlessness to it that you can't understand if you haven't been in that situation."