Angelina Jolie made an unexpected revelation today that she recently underwent a preventive double mastectomy. The 37-year-old actress wrote an op-ed piece in the New York Times explaining that the extreme measure was taken because she carries a faulty gene which significantly increases her risk of breast cancer.

Angelina’s mother, Marcheline Bertrand, succumbed to breast cancer at the age of 56 after fighting it for almost a decade. Angelina also carries a “faulty gene” which increases her chances for both breast and ovarian cancers. When Jolie found out that she was 87 percent more likely to be diagnosed with breast cancer than the average woman and 50% more likely for ovarian cancer, she decided to cut down her risk and have a double mastectomy.

“Once I knew that this was my reality, I decided to be proactive and to minimize the risk as much I could,” Angelina wrote.  “I made a decision to have a preventive double mastectomy. I started with the breasts, as my risk of breast cancer is higher than my risk of ovarian cancer, and the surgery is more complex.

“On April 27, I finished the three months of medical procedures that the mastectomies involved. During that time I have been able to keep this private and to carry on with my work,” Jolie explained. “But I am writing about it now because I hope that other women can benefit from my experience. Cancer is still a word that strikes fear into people’s hearts, producing a deep sense of powerlessness. But today it is possible to find out through a blood test whether you are highly susceptible to breast and ovarian cancer, and then take action…”