Angelina Jolie is "heroic" for going through a double mastectomy, her partner and the father of her children said. Brad Pitt has spoken in support of his fiancée after she revealed that she underwent a preventive surgery to decrease her chances of having breast cancer.

In a New York Times op-ed titled "My Medical Choice," the A-list Hollywood actress revealed that she has undergone a preventive double mastectomy surgery beginning on February 2 after her doctors told her she had 87% chance of getting breast cancer and 50% chance of ovarian cancer.

Her mother, actress Marcheline Bertrand, died of ovarian cancer in 2007 at 56.

Jolie said she made the difficult decision so her children don't need to fear that they will lose her from cancer. She also hoped that women reading her piece would learn from her experience, and that they, too, will undergo cancer testing.

Pitt, who has six children with Jolie, has praised the actress for her choice.

"Having witnessed this decision firsthand, I find Angie's choice, as well as so many others like her, absolutely heroic. I thank our medical team for their care and focus," he told the Standard.

"All I want is for her to have a long and healthy life, with myself and our children. This is a happy day for our family."

Jolie commended Pitt in her editorial article, saying that he was by her side during her the whole ordeal.

"I am fortunate to have a partner, Brad Pitt, who is so loving and supportive. So to anyone who has a wife or girlfriend going through this, know that you are a very important part of the transition.

"Brad was at the Pink Lotus Breast Centre, where I was treated, for every minute of the surgeries. We managed to find moments to laugh together. We knew this was the right thing to do for our family and that it would bring us closer. And it has."

It's not just Pitt who has Jolie's back. Their family has also voiced out their support for the 37-year-old star.

"My sister, like our mother, always put her children first. I am so grateful to be her brother," her brother James Haven said in a statement.

"My love and admiration for her can never be measured in words. I think she is an inspiration to many people who are faced with the same situation," her father, Oscar winner Jon Voight, with whom she has had a difficult relationship in the past, told E! News.

"I think she is quite magnificent in the way she is handling this. She is taking care of things. She does careful diligence and she has this courage to gather information and make decisions from it. It has been very successful and I heard she was able to travel soon afterwards.

"She is an amazing person. She is also an extraordinary mother. She includes them [her children] when she can without scaring them, and makes it understandable to them"

Pitt's mother, Jane, has also praised her soon-to-be daughter-in-law, saying in a statement, "We're so very proud of Angie, this means so much to our family especially our grandchildren. We love her dearly."