'Grateful': Olivia Munn thanks fans after revealing her breast cancer diagnosis

Olivia Munn has thanked her fans and followers for their support after her breast cancer diagnosis.

The actress, 43, revealed she underwent a double mastectomy following the diagnosis.

In an Instagram Story, Munn said she was "really grateful for all the love and support I've received about my diagnosis that I shared yesterday".

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"Reading your stories and comments has really meant a lot to me and I just wanted to express my gratitude for all of it," she added, alongside love heart emojis.

The actress revealed the diagnosis in an emotional social media post, sharing a series of photos taken while she underwent treatment in hospital last year.

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She also detailed how the diagnosis came to be, in an effort to "help others find comfort, inspiration and support on their own journey".

"In February of 2023, in an effort to be proactive about my health, I took a genetic test that checks you for 90 different cancer genes," she said.

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"I tested negative for all, including BRCA (the most well-known breast cancer gene). My sister Sara had just tested negative as well. We called each other and high-fived over the phone. That same winter I also had a normal mammogram."

"Two months later I was diagnosed with breast cancer.

"In the past ten months I have had four surgeries, so many days spent in bed I can't even count and have learned more about cancer, cancer treatment and hormones than I ever could have imagined.

"Surprisingly, I've only cried twice. I guess I haven't felt like there was time to cry. My focus narrowed and I tabled any emotions that I felt would interfere with my ability to stay clearheaded."

Munn credited her proactive gynaecologist, Dr Thais Aliabadi - who also counts the Kardashians, Jenners and Brooke Shields among her celebrity clients - for the discovery that could have done unnoticed another year, when her next routine mammogram was scheduled for.

"Dr Aliabadi looked at factors like my age, familial breast cancer history, and the fact that I had my first child after the age of 30," the actress said.

"She discovered my lifetime risk was at 37 per cent. Because of that score I was sent to get an MRI, which led to an ultrasound, which then led to a biopsy. The biopsy showed I had Luminal B cancer in both breasts. Luminal B is an aggressive, fast moving cancer."

The X-Men: Apocalypse star said she had kept her health battle private until now as she "needed to catch my breath and get through some of the hardest parts before sharing".

Her partner, comedian John Mulaney, was among the big names who commented on her post, sharing a heartfelt debt of gratitude to the actress.

"Thank you for fighting so hard to be here for us. Malc and I adore you," he wrote, referring to their son, Malcolm.

Many other celebrities flooded the post with messages of support, including Modern Family's Ariel Winter and Big Bang Theory's Kaley Cuoco.

"Thank you for sharing this! Wow," Cuoco wrote.

"Sending you and your family love & healing vibes. You are so strong," Winter said.

Oscar-winner Jessica Chastain applauded her honesty.

"You are very generous to share your story," she told Munn.

"I believe in doing so, you've saved lives. So much love to you and your family."