Nicole Kidman says her Oscar-nominated role as a bereaved mother in the film Rabbit Hole left her deeply disturbed.
Kidman has had rave reviews for her performance in the film.
But as a mother herself the actress tells BBC Radio Four's Front Row she found it hard going.
"I knew before going into it that it was dangerous, but I couldn't foresee the way it was going to disturb me on such a deep level."
Kidman stars in Rabbit Hole alongside Aaron Eckhart. They play Becca and Howie, a couple struggling to cope with the death of their young son.
Kidman says it was an emotionally gruelling role to play but tells Mark Lawson she wanted to confront her own fears.
"At the same time as it disturbed me, it was also walking through something that is probably one of my biggest fears, and that's not necessarily a bad thing.
"And the way in which the film and the play has been constructed there's an enormous amount of hope in the story."
The film is based on a play by the Pulitzer prize-winning writer David Lindsay-Abaire. Sex and the City star Cynthia Nixon won a Tony award for her portrayal of Becca on Broadway.
But Kidman says she deliberately did not go to see Nixon in the role: "I read the play but part of me was, 'I don't want to see someone else in the performance then that will imprint on me'.
"And Cynthia Nixon is such a powerful actress that I would probably have been intimidated and ended up not doing it."
It was a review of the play which initially intrigued her because despite the heavy subject matter she says "the review said it was funny and never sentimental and very, very real".
"I thought 'Ah that's how this subject matter should be handled' and that's what drew me to it."
In the film the couple try to find their way back to a life that still holds the potential for beauty, laughter and happiness.
'Lean and mean'
Kidman was also a producer on the film. She says she encouraged a "lean and mean" budget, which she believes helped get the film made.
And she came up with a number of money-saving ideas: "I go, 'We don't need trailers, I'll sit in the car if we're shooting on the street and you can call me when you need me to do the scene' and that saves an enormous amount of money."
Kidman was even prepared to do her own make-up to cut costs: "We can share one make-up artist for all of us, I can do my own make-up if needs be. That's the sort of contribution that I find really good."
Kidman says her production company Blossom Films is committed to developing more films with strong roles for women, but not just for her to star in.
She says she wants to create roles "for women of all different ages, to give female actors a great chance".
"There are some extraordinary roles for women this year, that are probably much better than the male roles and that's great, but that's a rare year."
Kidman lost to Natalie Portman - star of Black Swan - at the Golden Globes but has been nominated for a best actress Oscar.
Critics have questioned some of her film choices in the past and Kidman admits her decisions are based on instinct: "When I choose to do something it's really rapid and quick and then I'm like 'Oh my God what have I done'."
She says this has led to regrets about roles she has accepted in the past: "I don't want to give examples but I'm sure you can look at my work and see where."
Soon after the Golden Globe awards the actress and her country singer husband Keith Urban announced they had become parents again through a surrogate.
The couple now have two daughters and Kidman also has two adopted children with her ex-husband, Tom Cruise.
There have been numerous articles about her new baby but Kidman says she avoids reading anything about herself.
"(I'm) Blissfully ignorant, I never read it and I don't have people around me that tell me about it. And I don't think I'm that well known any more, I think I've slipped down which is fine," she says.
The actress lives away from Hollywood in Tennessee in order to maintain her privacy, so she is less "available", and will not be following the trend of movie star tweeters.
"That's not me, I feel very uncomfortable with that. I don't want to know what people are eating or when they went to the bathroom."
She also says any future acting roles depend on her family: "I'm just deciding whether I can go and do something on Broadway at the end of this year, we're trying to pull that together for around December.
"I just have to work my whole family situation because I have to get my husband to say 'OK, I can come to New York for four or five months' and we'll set up camp there for a while."