Angelina Jolie has revealed she has had a preventative double mastectomy after learning she was likely to develop breast cancer.

Writing in the New York Times, the actress said she finished three months of medical procedures on April 27 and her "loving and supportive" partner Brad Pitt was at the hospital for every minute of the surgeries.

Angelina's mother died of the disease when she was 56 and the Hollywood star said her children had asked if the same could happen to her.

In a moving column for the newspaper, Angelina, 37, wrote of her mother: "She held out long enough to meet the first of her grandchildren and to hold them in her arms. But my other children will never have the chance to know her and experience how loving and gracious she was."

She added that she carries the "faulty" gene, BRCA1, which increases her risk of developing breast cancer to 87% and ovarian cancer to 56%.

The mother-of-six revealed she began surgery on February 2 and kept her ordeal private, but has decided to speak out about her procedures so other women can benefit from her experiences.

She described one of the operations as "like a scene out of a science-fiction film," but added that after nine weeks her final surgery is complete with her breasts reconstructed with implants.

Speaking about her children, she wrote: "It is reassuring that they see nothing that makes them uncomfortable. They can see my small scars and that's it. Everything else is just Mommy, the same as she always was. And they know that I love them and will do anything to be with them as long as I can."

She added that she does not feel less of a woman, rather that she is empowered to have made a strong choice.