Actor Alec Baldwin announced the death of his mother, Carol Baldwin, in a heartfelt post on Instagram.

Baldwin revealed that his mother died Thursday at the age of 92. The actor wrote, "Carol M. Baldwin, mother of actors Alec, Daniel, William and Stephen Baldwin and two daughters, Elizabeth and Jane, died today in Syracuse, New York."

Alec Baldwin

Alec Baldwin speaks during the 2021 RFK Ripple Of Hope Gala at New York Hilton Midtown on December 09, 2021, in New York City. (Dimitrios Kambouris/Getty Images)

The star went on to describe his mother's life and accomplishments. He said she was born in December 1929 and had one brother and five sisters. 

She met her husband, Alexander R. Baldwin Jr., who was nicknamed Alec, while they were both students at Syracuse University. The family moved to Long Island in 1954 where Alec taught history and coached football and riflery at Massapequa High School until his death in 1983 at age 55. 

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Carol Baldwin Death

Actor Alec Baldwin announced the death of his mother Carol Baldwin in a heartfelt Instagram post on Thursday. The post featured a vintage photo of Carol alongside a more recent picture. (Alec Baldwin/Instagram)

He said his mother raised her children and then went on to work in marketing research for a firm called Quick Test.

She was diagnosed with breast cancer in 1991. After beating the disease, she became involved in breast cancer support groups and eventually launched the Carol M Baldwin Breast Cancer Research Fund on the campus of SUNY Stony Brook. Another branch was later opened at SUNY Upstate University. 

Baldwin said the fund has helped raise millions of dollars for the breast cancer cause.

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"My mother taught me about second acts. And third ones, too," the 64-year-old actor wrote of his mother. "She spent the last 25 years of her life as a fighter and a champion for the cause to which she devoted so much energy. We are all enormously proud of her accomplishments."

In closing, Baldwin said his mother had 25 grandchildren and 14 great-grandchildren.

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Hailey Bieber Grandmother Death

Hailey Bieber reacts to the death of her grandmother on Instagram. (Hailey Bieber/Instagram)

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Several stars posted their condolences in the comments. Actress Julianne Moore, 61, wrote, "I'm so sorry" along with a broken heart emoji. Baldwin's wife, Hilaria Baldwin, 38, simply posted a heart emoji.

Stephen Baldwin's daughter, Hailey Bieber, 25, honored her grandmother by sharing Alec's post to her Instagram story, writing, "We love you Grandma." She also included a white heart and dove emoji.