Kathy Griffin's Mother Maggie Dies at 99 After Battle with Dementia: 'I Am Gutted,' Says Kathy

Kathy Griffin 's mother Maggie has died, just months before her 100th birthday.

The comedian, 59, announced the sad news on Tuesday evening, while sharing a sweet photo of the two.

"My mom, the one and only Maggie Griffin, passed away today," Kathy wrote. "I am gutted. My best friend. I'm shaking. I won't ever be prepared."

"I'm so grateful you guys got to be part of her life," Kathy added. "You knew her. You loved her. She knew it. Oh, and OF COURSE she went on St. Patrick's Day. 💔 💔 💔."

Her message was met with a sea of support from friends and loved ones, including Chrissy Teigen, Sharon Stone, Rosanna Arquette, Mario Cantone, Audra McDonald, and more.

"Oh Kathy. I am so, so sorry," Teigen wrote. "We love you."

"She was such a light," Cantone added. "Funny and strong. Sending you all my love."

Born Margaret Mary Corbally on June 10, 1920 in Chicago, Illinois, according to her IMDb profile, Maggie worked as a hospital administrator before she later went on to star on two of Kathy's shows: Kathy Griffin: My Life on the D-List (2005-10) and Kathy (2012-13).

In June 2010, she released a book, Tip It!: The World According to Maggie.

"You know how a box of wine is never empty just because the spigot seems to have run dry (There's always a little more if you just tip it!)," she wrote about what readers could expect of her book. "This book is like that. There's so much in it - never-before-published Griffin family photos!, a love story (me and my dear departed husband Johnny), a whole guide to good living (including how to survive on what's in your purse), and a lot of funny business in this book from Kathleen (she made comments in this book; readers, I was not able to stop her!)."

While appearing on the series, Maggie became a reality TV star in her own right. "Mother, Grandmother, Wine Connoisseur," is how she described herself on her Instagram account, which was filled with humorous posts of herself alongside her comedian daughter throughout the past few years.

"Can't a woman eat in peace g-damnit! Go home Kathleen! Love, Mom," Maggie captioned a photo of herself alongside Kathy in October 2014.

"So proud of my baby girl making the papers!" Maggie wrote about another image of the mother-daughter duo.

Back in January 2019, Kathy revealed that Maggie had been diagnosed with dementia.

"The pic below, taken in [September 2018], was the last time I was able to have a proper/coherent conversation with her," Kathy had tweeted. "Since that photo was taken, she has rapidly fallen into the throes of dementia. This is never easy for any child, I know this is a reality that millions of people deal with every year. But when it comes to my mom this is particularly hard because her sharp mind was everything."

"In terms of how she is now, at this point she only knows my name and I love you," Kathy said. "I know many of you know what that reality is like...I'm still grappling with it. Up until these past couple years she was so sharp she always kept me on my toes. Her mind was so naturally quick, funny, and smart. No one could get anything past her. Watching that slip away so fast has been devastating."

Last June, Kathy gave an update on her mom's health, on her 99th birthday.

"Today is my mother Maggie's 99th Birthday. I spoke with her yesterday and, unfortunately, I'm sorry to say her dementia is worsening," Kathy said, sharing an old red carpet photo of the mother-daughter pair. "Here's a fun picture to celebrate happier times."

The Griffin family has experienced difficult health crises in the last few years. Kathy's older siblings Gary and Joyce both died of cancer, in 2014 and 2017, respectively.

Maggie was married to John, a retired electronics store manager, for decades up until his death in February 2007. In addition to Kathy, Gary, and Joyce, the two also had sons John and Kenny.

Speaking with PEOPLE in March 1997, Kathy insisted her often dark humor came from observing her family as a kid in Oak Park, IIinois: "I come from a veritable Irish Catholic freak show," Kathy joked. "My parents still think it's the Depression."