John Mulaney Supports Olivia Munn After She Shares Breast Cancer Battle

John Mulaney is sending all his love to Olivia Munn.

After the actress shared she was diagnosed with breast cancer in 2023, the comedian—with whom she shares 2-year-old son Malcolm—sent her a heartfelt message. 

"Thank you for fighting so hard to be here for us," John, who confirmed his relationship with Olivia in 2021, wrote on Instagram March 13 underneath her post announcing the news. "Malc and I adore you."

And he wasn't the only star to share kind words. Lindsey Vonn told Olivia, "You are brave and strong and I'm thankful you are ok. Sending all the love."

Kaley Cuoco also thanked her for detailing her journey to help others. "Thank you for sharing this!" she added. "Wow."

As Olivia explained in her post, she took a genetic test that she said scans for 90 different cancer genes in February 2023 to be proactive about her health. And when she got the results back, she wasn't concerned.

"I tested negative for all, including BRCA (the most well-known breast cancer gene)," she wrote. "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."

However, the X-Men: Apocalypse star noted she was diagnosed with breast cancer two months later and offered a glimpse inside what the past year has been like.

"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," she continued alongside photos from her doctor visits and time at the hospital. "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."

She also explained why she'd initially kept the diagnosis to herself.

"I've tended to let people see me when I have energy, when I can get dressed and get out of the house, when I can take my baby boy to the park," The Newsroom alum added. "I've kept the diagnosis and the worry and the recovery and the pain medicine and the paper gowns private. I needed to catch my breath and get through some of the hardest parts before sharing."

Ultimately, Olivia is grateful her OBGYN calculated her Breast Cancer Risk Assessment Score—noting "the fact that she did saved my life"—and encouraged others to ask about it, too.

"Because of that score I was sent to get an MRI, which led to an ultrasound, which then led to a biopsy," she wrote. "The biopsy showed I had Luminal B cancer in both breasts. Luminal B is an aggressive, fast moving cancer. 30 days after that biopsy I had a double mastectomy. I went from feeling completely fine one day to waking up in a hospital bed after a 10-hour surgery the next."

The 43-year-old also expressed her appreciation to the doctors and nurses for their care and to her friends and family who have been by her side.

"I'm so thankful to John for the nights he spent researching what every operation and medication meant and what side effects and recovery I could expect," she wrote. "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."

To read more stars' messages of support for Olivia, keep reading.

After Olivia Munn shared her breast cancer diagnosis on Instagram March 13, she received a flood of well-wishes from fans, friends and fellow stars.

"Thank you for fighting so hard to be here for us," the comedian wrote to his partner. "Malc and I adore you."

"Thank you for sharing this!" the Big Bang Theory actress commented on Instagram. "Wow."

"You are so strong Olivia!" the Fellow Travelers star wrote. "Grateful you found this early. Sending you love always."

"Sending you and your family love & healing vibes," the Modern Family alum commented. "You are so strong."

"I love you friend," the Emmy winner told her pal. "May God continue to bless you with good health and a long happy life."

"Your experience is so powerful to share!" the Sex and the City actress commented. "Sending you so much love and strength , so grateful you found out early and can only imagine the emotional roller coaster you have been on."

The Office alum commented, "I love you."

"You are brave and strong and I’m thankful you are ok," the Olympic athlete wrote. "Sending all the love."