Angelina Jolie: 'I Feel Wonderful'

The London premiere of Brad Pitt's new movie World War Z marked Angelina Jolie's first public appearance since announcing her double mastectomy, and she used the occasion to thank those that have applauded her brave decision.

"I feel wonderful, and I'm very grateful for all the support," Jolie, 37, told reporters as she made her way down the red carpet in a simple black Saint Laurent gown. "It's meant a lot to me."

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In an op-ed piece for the The New York Times, the Oscar-winning actress revealed that she recently underwent a preventive double mastectomy after being told that she had an 87-percent chance of contracting breast cancer.

"I've been very happy to see the discussion about women's health expanded," Angelina said at Sunday's premiere. "That means the world to me, and after losing my mom to these issues I'm very grateful for it."

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Jolie lost her mother, Marcheline Bertrand, to ovarian cancer when Bertrand was only 56. More recently, the actress also lost an aunt, who died of breast cancer just weeks after Jolie's announcement.

Brad Pitt told Sky News that Jolie's decision was heroic -- both to undergo the surgery as well as go public with it.

"I'm very proud and just relieved that that's not going to be the thing that takes her out," said Pitt. "The biggest fear as a father is keeping the family alive and safe and together, and she did that for us."

Check out Jolie and Pitt back on the red carpet in the video above.