The mother of the famous comedian was the breakout star of the reality show My Life on the D-List.

Maggie Griffin died Tuesday at age 99.

Kathy Griffin confirmed the news of her mother's passing in a post on Twitter. “My Mom, the one and only Maggie Griffin, passed away today. I am gutted. My best friend. I’m shaking. I won’t ever be prepared," she wrote. The comedian also posted an image of the pair sitting poolside, with Maggie raising a glass.

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

"It truly feels like the end of an era," she added in a longer post to Instagram.

Maggie was the breakout star of My Life on the D-List, appearing for six seasons alongside her daughter on the Bravo reality series. Her wit and love of boxed wine endeared her to fans.

Maggie also appeared in the comedian's documentaries, Kathy and Kathy Griffin: A Hell of a Story, which showed the matriarch as a major source of support for Kathy after she was photographed with a bloody mask of President Trump and endured international backlash.

Last year, Kathy revealed in a social media post that her mother had "rapidly fallen into the throes of dementia" and was under 24-hour care. In the Instagram caption, she acknowledged how proud she was that D-List "gave me the opportunity to show the world how naturally funny my parents were." John Griffin, her father and Maggie's husband, died in 2007.

"When people tell me they feel like they know my mom, I always respond 'you do!' She never put on a show, she was the show," Kathy wrote. "If you ever met my mom and asked for a photo, you should know it was a pleasure as much for her as it was for you. She loved making people happy and making people laugh. And trust me, I know she was the bigger star...thank you from the bottom of my heart for giving us a lifetime of memories."