Christina Applegate believes she was living with MS for years before she was diagnosed.

Christina Applegate is part of a sisterhood she never wanted to be.

In a conversation on “Good Morning America” that aired on Wednesday, the “Dead To Me” star was joined by her friend Jamie-Lynn Sigler to talk about living with multiple sclerosis (MS).

They both have the autoimmune disease that affects the central nervous system. Applegate credited Selma Blair, who was diagnosed with MS in 2018 and had co-starred with Applegate in “The Sweetest Thing,” with encouraging her to see a doctor.

“She goes ‘You need to be checked for MS.’ I said ‘No, really?,” Applegate recalled. “The odds, the two of us from the same movie, come on, that’s not gonna be, that doesn’t happen. If not for her, it could have been way worse.”

Applegate first shared she was diagnosed with MS in August of 2021. She said she now realizes that she probably had it for years prior to her diagnosis.