Jessica Chastain Reveals Her ‘Beautiful Grandma Marilyn’ Has Been Diagnosed with Breast Cancer: ‘She’s a Total Badass’

Mar. 15, 2025

Jessica Chastain (right) with her grandmother Marilyn Herst.Photo:Taylor Hill/FilmMagic

Taylor Hill/FilmMagic

Jessica Chastainis sharing a health update about her grandmother Marilyn Herst.The Oscar winner, 47, revealed in anInstagrampost on Friday, Oct. 11, that her beloved grandmother has beendiagnosed with breast cancer.“My beautiful grandma Marilyn, who many of you have met at different events, was recently diagnosed withbreast cancer,” Chastain wrote.“This week, I flew to meet with her amazing doctors and surgeons who are providing her the best possible care,” theMothers' Instinctstar continued. “I’m beyond grateful to the incredible hospital staff.”She added, “She’s a total badass, and I know she’ll get through this. 💪🏼.“Jessica Chastain’s grandmother Marilyn Herst in a photo shared on Oct. 11, 2024.Jessica Chastain/Instagram"In honor of Breast Cancer Awareness Month, she asked me to remind all of you: schedule your mammogram today,” the actress added.“You are so important to so many people—please make this a priority. 💖 #BreastCancerAwareness #GetChecked #EarlyDetection"The Instagram post also featured a video of Herst telling her and Chastain’s followers about how she felt a small lump in her breast, mentioned it to her doctors during her annual exam and received a mammogram.The PEOPLE Puzzler crossword is here! How quickly can you solve it? Play now!Herst is now being treated for breast cancer. “I feel so grateful for the fact that I found it so early because it’s so treatable,” she said. “But if you don’t take care of yourself and check yourself or even have your regular mammograms, you may not catch it early and it may not help you.““So I really want you to go out and do that. Please, for me,” Herst asked. Chastain also added, “For grandma! Go get your mammograms immediately please.“Marilyn Herst and Jessica Chastain in a photo shared on Oct. 11, 2024.Jessica Chastain/InstagramNever miss a story — sign up forPEOPLE’s free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.Chastain has a close relationship with her grandmother.The Wall Street Journalreported that Herst moved in with the actress during the COVID-19 pandemic lockdown.The duo spent quality time together and worked out several times a week.Chastain once told a funny story about Herst in January 2022, recalling howher grandma sat on a fellow actor’s lap at a partythe actress hosted.“A few years ago I had a party at my house andBradley Cooperwas there. My grandmother is now at the age where she just really doesn’t care, you know? She’s just like, ‘I’m just gonna do whatever I want,’ " Chastain recalled during an appearance onThe Ellen DeGeneres Show.Jessica Chastain and Marilyn Herst at the 2023 Tony Awards.Kevin Mazur/Getty"So in the middle of the party, she just walked over to Bradley and just sat on his lap,” she continued. “He looked horrified, actually. He had never met her. He didn’t know who she was.““I saw it kinda happening in slow motion where I was like, ‘No!’ I just started going, ‘It’s my grandma! It’s my grandma!’ Then he was like, ‘Okay. Hi, grandma…,’ " theInterstellaractress added.

Jessica Chastainis sharing a health update about her grandmother Marilyn Herst.

The Oscar winner, 47, revealed in anInstagrampost on Friday, Oct. 11, that her beloved grandmother has beendiagnosed with breast cancer.

“My beautiful grandma Marilyn, who many of you have met at different events, was recently diagnosed withbreast cancer,” Chastain wrote.

“This week, I flew to meet with her amazing doctors and surgeons who are providing her the best possible care,” theMothers' Instinctstar continued. “I’m beyond grateful to the incredible hospital staff.”

She added, “She’s a total badass, and I know she’ll get through this. 💪🏼.”

Jessica Chastain’s grandmother Marilyn Herst in a photo shared on Oct. 11, 2024.Jessica Chastain/Instagram

Jessica Chastain/Instagram

“In honor of Breast Cancer Awareness Month, she asked me to remind all of you: schedule your mammogram today,” the actress added.

“You are so important to so many people—please make this a priority. 💖 #BreastCancerAwareness #GetChecked #EarlyDetection”

The Instagram post also featured a video of Herst telling her and Chastain’s followers about how she felt a small lump in her breast, mentioned it to her doctors during her annual exam and received a mammogram.

The PEOPLE Puzzler crossword is here! How quickly can you solve it? Play now!

Herst is now being treated for breast cancer. “I feel so grateful for the fact that I found it so early because it’s so treatable,” she said. “But if you don’t take care of yourself and check yourself or even have your regular mammograms, you may not catch it early and it may not help you.”

“So I really want you to go out and do that. Please, for me,” Herst asked. Chastain also added, “For grandma! Go get your mammograms immediately please.”

Marilyn Herst and Jessica Chastain in a photo shared on Oct. 11, 2024.Jessica Chastain/Instagram

Never miss a story — sign up forPEOPLE’s free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.

Chastain has a close relationship with her grandmother.The Wall Street Journalreported that Herst moved in with the actress during the COVID-19 pandemic lockdown.

The duo spent quality time together and worked out several times a week.

Chastain once told a funny story about Herst in January 2022, recalling howher grandma sat on a fellow actor’s lap at a partythe actress hosted.

“A few years ago I had a party at my house andBradley Cooperwas there. My grandmother is now at the age where she just really doesn’t care, you know? She’s just like, ‘I’m just gonna do whatever I want,’ " Chastain recalled during an appearance onThe Ellen DeGeneres Show.

Jessica Chastain and Marilyn Herst at the 2023 Tony Awards.Kevin Mazur/Getty

Kevin Mazur/Getty

“So in the middle of the party, she just walked over to Bradley and just sat on his lap,” she continued. “He looked horrified, actually. He had never met her. He didn’t know who she was.”

“I saw it kinda happening in slow motion where I was like, ‘No!’ I just started going, ‘It’s my grandma! It’s my grandma!’ Then he was like, ‘Okay. Hi, grandma…,’ " theInterstellaractress added.

source: people.com