Apart from the physical toll, the emotional impact has been a major challenge, particularly for her family.
“My daughter’s had to see the loss of her mum, in the way that I was a mum with her,” Applegate told People magazine.
“Being present, out of the house, out of my bed. She doesn’t see those things anymore. If she comes in my room and sees I’m laying on my side, she knows she can’t ask me to do anything. And that breaks me. Because I love doing stuff for my kid.”
While heartbreaking, the actress won’t let it take her down.
“I know I’ll live a long enough life to experience my kid and the things she’s going to do,” she continued. “And I need to be here, so I’ve got to fight. I got to fight.”
Applegate shared that after noticing tingling in her toes while filming the final season of Dead to Me, she went to the doctor at the urging of her friend – and co-star in 2002’s The Sweetest Thing – Selma Blair, 51, who was diagnosed with the condition in 2019.
She’s since leaned on Blair for support and has also become incredibly close to The Sopranos actress Jamie-Lynn Sigler, 42, who was diagnosed with the condition when she was just 20 years old.
“If I didn’t have her, I wouldn’t be able to do this life thing,” Applegate told People while promoting their new podcast, MeSsy (launching March 19).
“She’s the only person who really knows me. I can talk about anything with her.”
Sigler, who was introduced to Applegate through their mutual friend Lance Bass, is a willing cheerleader.
“It can be easy to forget all the other parts of yourself and let this disease define you,” she said.
“It’s important as Christina’s friend to remind her of her greatness.”
Applegate, who was born in Hollywood and starred in TV ads as an infant and on soap operas as a child, faced another health hurdle in 2008 when she was diagnosed with breast cancer and underwent a double mastectomy.
A decade later, having tested positive for the cancer-causing BRCA gene, she had her ovaries and fallopian tubes removed.
Living with MS, she says, is her toughest test to date.
“It sucks, it’s not my favourite disease. I’ve had a couple,” she told GMA. “I’m never gonna wake up and go, ‘This is awesome.’ Like it’s just not gonna happen … But I might get to a place where I will function a little bit better.”
Sigler sees so much more. “All I want her to do is remember how incredibly special she is. I tell her all the time, ‘You’re Christina motherf--king Applegate!’” she told People.
“So right now, I’ll hold the big dreams for both of us.”