Olivia Munn has revealed that she was diagnosed with breast cancer and underwent a double mastectomy, thanking her doctors and urging fans to calculate their own risk assessment. "I'm lucky. We caught it with enough time that I had options. I want the same for any woman who might have to face this one day," the 43-year-old actor posted on Instagram on Wednesday with photos and a video of her being treated at a hospital.Munn said she took a genetic test in February 2023 that checks for 90 different cancer genes and was negative for all. Even so, her doctor decided to calculate her Breast Cancer Risk Assessment Score and that "saved my life," Munn wrote.Recording a high score, Munn got a biopsy, which found she had an aggressive form of cancer in both breasts. She had a double mastectomy 30 days after the biopsy and has had four surgeries in the past 10 months. She said she kept it private because "I needed to catch my breath and get through some of the hardest parts before sharing."Munn thaked family and friends, especially her partner, comedian John Mulaney, "for being there before I went into each surgery and being there when I woke up, always placing framed photos of our little boy Malcolm so it would be the first thing I saw when I opened my eyes."Munn was a correspondent on "The Daily Show with Jon Stewart" and her movie credits include "Magic Mike," "The Predator," "Office Christmas Party" and "X-Men: Apocalypse."