Kathy Griffin revealed on Thursday that her mother Maggie is suffering from dementia.

"As heartbreaking as this is, I feel the need to share some important info about my mom Maggie. I've always been honest with you all, but this one is really hard," the 58-year-old comedian told her Twitter followers. "The pic below, taken in September, was the last time I was able to have a proper/coherent conversation with her.

"Since that photo was taken, she has rapidly fallen into the throes of dementia," Griffin continued. "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."

Griffin went on to explain that her mom's rapid decline, from someone who was quick and sharp, has been difficult to watch.

"My mom is 98 and up until this 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."

The "Fashion Police" alum added that "at this point" her mom "only knows my name and I love you."

"I know many of you know what that reality is like...I'm still grappling with it," wrote Griffin, noting that her mom is "getting the best 24-hour care" and isn't in pain.

She added: "A big reason I'm sharing this news with you is that so many of you have asked why I haven't posted a video of Maggie & her beloved dog Twinkle in the past few months. Now you understand why we haven't been able to share anything, here is a moment between them from this summer."

In addition to the clip of her mom with her pup Twinkle, Griffin shared several other sweet photos and videos of her mom, as well as reflected on Maggie's time appearing on Griffin's Bravo reality series, "My Life on the D-List," from 2005 to 2010.

"What I am most proud of when I comes to My Life On The D List is that show gave me the opportunity to show the world how naturally funny my parents were. 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," Griffin gushed before asking fans to share their own favorite Maggie moments.