Christina Applegate Details Day She Found Out She Has MS: 'It Sucked'

While appearing on this week's episode of SiriusXM’s "This Life of Mine with James Corden," the 52-year-old actress detailed the day she found out her life had changed.

During the interview, the former late night host broached the subject by first cautiously asking, "Are you okay to talk about when you were diagnosed and what that day was like?"

"Yeah, it sucked. I was feeling so ill for so many months," Applegate began, before Corden questioned if she had been "ignoring" feeling ill.

"For years and years and years," Applegate said, before listing symptoms such as balance issues, speech issues, shaking hands and at times her knee "would go out" during tennis.

However, she would find excuses to explain away what she was going through.

"It was like, 'Oh, I'm dehydrated. It's too hot out. Whatever.' January of 2021, when my mom was diagnosed right before Christmas with cancer, I noticed that my toes got numb and I ignored it and I still was hiking and then I'd be like, 'Whoa, that's, hmm. That's a weird muscle spasm,'" she explained, before recalling what made her decide to get tested.

The actress was about to begin filming the last season of Dead To Me and she found things "started to get weirder and weirder."

"By this time I was like, 'You guys, I can't even walk up the steps to my trailer.' After some tests, they did an MRI in my brain and it was a Monday and we were at work and my doctor said, 'I really need to get on a Zoom with you to go over your MRI results,' and I remember saying to them, 'I have to leave. I have to go home and be there at seven,' and they're like, 'Well, we have like one more scene to do,' and I just said, 'I can't. I gotta go home.'"

She then left set and went home to meet with her doctor, who revealed her diagnosis for MS.

"I opened up my Zoom and there he was and he just looked at me and he goes, 'I'm so sorry,' and I was like, 'What do you mean?' and he goes, 'Here's a picture of your brain. Sorry,' and there's like 30 lesions all over my brain and I went, 'No, please don't tell me this. Please don't tell me this,'" she said.

Through tears, Applegate revealed how production for the Netflix series reacted to her diagnosis.

"I had to call production. I said, 'You guys, it's f--king MS,' and they're like, 'Okay, we're shutting down for the week.' That was it, and then we were just trying to figure out how to film and stuff and we did. I mean, we finished it. It took us a long time, but we finished it. But yeah, I remember that moment like it was yesterday."

Applegate first announced her multiple sclerosis diagnosis -- a "potentially disabling disease of the brain and spinal cord (central nervous system)," per the Mayo Clinic -- in August 2021.

She has since teamed up with Jamie-Lynn Sigler -- who was also diagnosed with MS -- to share their journey with the disease on their podcast MeSsy, which Sigler described as having the listener "eavesdropping" on their intimate conversations.

While it can be messy, Applegate's hope is that listeners feel seen and heard, no matter what it is that they're going through.

"I've been playing a character called Christina for 40 years, who I wanted everybody to think I was because it's easier," Applegate said during the pair's emotional sit-down with GMA's Robin Roberts, in February, admitting that she is opening up in a way she never has before. "But this is, it's kind of my coming out party. Like, this is... the person I've been this whole time. I was kind of putting on a little act for everybody for so long because I just thought that was easier -- be light, be funny ... don't make people uncomfortable. And I don't care anymore."

Along with her podcast, Applegate told Corden that reality television also helps her cope with the disease.

"Anyone who knows me well knows that it's on 24/7 in my room 'cause I don't leave my room very often. I know that sounds really depressing, but it's kind of like I just need to sleep sometimes," Applegate said on the podcast.

"Give me any of it. Give me a 'Vanderpump,' give me a 'Below Deck,' give me a housewife. Even give me like 'Kitchen Nightmares with Gordon Ramsey.' I'll watch like nine seasons of that in like two days," she added. "I love watching, the imperfections of real people really like, wow. Those people exist. I love that. That's why I love reality TV because they freak me out that they walk this earth acting like that."