"Yup. I turned 50 today. And I have MS. It's been a hard one," Applegate wrote.
"Sending so much love to all of you this day. Many are hurting today, and I am thinking of you," she added. "May we find that strength to lift our heads up. Mine currently is on my pillow. But I try."
In August, Applegate revealed her MS diagnosis on Twitter, writing that she had been diagnosed "a few months" prior to sharing the devastating news.
Yup. I turned 50 today. And I have MS. It’s been a hard one. Sending so much love to all of you this day. Many are hurting today, and I am thinking of you. May we find that strength to lift our heads up. Mine currently is on my pillow. But I try
"It's been a strange journey," she wrote. In the time since her diagnosis, the "Dead to Me" star shared that she has "been so supported by people that I know who also have this condition." Applegate also admitted that "it's been a tough road."
In a follow-up tweet, the "Married with Children" alum shared a piece of advice she'd received from a friend of hers who also has MS. "We wake up and take the indicated action," she quoted. "And that's what I do."
She then asked for privacy "as I go through this thing."
MS is an autoimmune disease that affects the central nervous system. It can impact the flow of information from the brain to the body -- though it manifests differently in different patients -- and is incurable.
Hi friends. A few months ago I was diagnosed with MS. It’s been a strange journey. But I have been so supported by people that I know who also have this condition. It’s been a tough road. But as we all know, the road keeps going. Unless some asshole blocks it.
There have been other celebrities who have shared their own journey with MS, including Jack Osbourne, Jamie Lynn Sigler and Selma Blair, who starred alongside Blair in the 2002 film "The Sweetest Thing."
After Applegate shared her diagnosis, Blair offered her support to her former co-star. The actress -- who has been very public with her own experiences with MS -- commented on Applegate's post about her diagnosis, writing, "Loving you always. Always here. As are our kids. Beating us up with love."
Applegate was previously open about another health crisis when she was diagnosed with breast cancer in 2008.
She opted for a double mastectomy, working that choice into the narrative of her Netflix series, "Dead to Me."