After having a preventive double mastectomy in 2013 to reduce the risk of getting cancer, mom-of-six Angelina Jolie – who lost her mother, grandmother and aunt to the disease – got a troubling phone call from her doctor two weeks ago.

In a New York Times op-ed piece published early Tuesday, Jolie, 39, says she had her ovaries and fallopian tubes removed last week because she carries a gene that gave her a 50 percent risk of developing ovarian cancer.

“I went through what I imagine thousands of other women have felt,” Jolie writes. “I told myself to stay calm, to be strong, and that I had no reason to think I wouldn’t live to see my children grow up and to meet my grandchildren.”

After hearing the news, she called her husband, Brad Pitt, who was on a plane within hours.

“The beautiful thing about such moments in life is that there is so much clarity. You know what you live for and what matters. It is polarizing, and it is peaceful,” she shares.

The Academy Award-winning actress went to see the surgeon who had treated her mother Marcheline, who died in 2007 of ovarian cancer.

“She teared up when she saw me: ‘You look just like her,’ ” Jolie writes. “I broke down.”

Jolie had to wait another five days for test results that would reveal whether there was cancer somewhere in her body. “I passed those five days in a haze, attending my children’s soccer game, and working to stay calm and focused.”

When the wait was over, she learned that the tumor test was negative.

“I was full of happiness, although the radioactive tracer meant I couldn’t hug my children,” she shares. “There was still a chance of early stage cancer, but that was minor compared with a full-blown tumor. To my relief, I still had the option of removing my ovaries and fallopian tubes and I chose to do it.”

That said, the surgery would push her into forced menopause.

“It is a less complex surgery than the mastectomy, but its effects are more severe,” she writes. “It puts a woman into forced menopause. So I was readying myself physically and emotionally, discussing options with doctors, researching alternative medicine, and mapping my hormones for estrogen or progesterone replacement.”

Last week Jolie had “a laparoscopic bilateral salpingo-oophorectomy.” The surgery revealed a small benign tumor on one ovary but no signs of cancer in the other tissues. The mom-of-six chose to keep her uterus because there is no history of uterine cancer in her family.

She now wears a small clear patch that delivers bio-identical estrogen and has a progesterone IUD inserted in her uterus that will help her maintain a hormonal balance.

“Regardless of the hormone replacements I’m taking, I am now in menopause,” she shares. “I will not be able to have any more children, and I expect some physical changes. But I feel at ease with whatever will come, not because I am strong but because this is a part of life. It is nothing to be feared.”

She goes on to say that having the surgery has not removed all risk. “The fact is I remain prone to cancer.” She writes that she is looking for natural ways to strengthen her immune system.

“I feel feminine, and grounded in the choices I am making for myself and my family,” she writes. “I know my children will never have to say, ‘Mom died of ovarian cancer.’ “