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CHICAGO — Actress Christina Applegate revealed she has been diagnosed with multiple sclerosis.

The 49-year-old “Dead to Me” star wrote on Twitter, “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.”  

She is asking for privacy as she takes on this new health challenge.  

She has previously discussed her 2008 battle with breast cancer, after which she had a double mastectomy as well as her ovaries and fallopian tubes removed.

Multiple sclerosis — also known as MS — affects the nervous system and often results in progressive physical and cognitive decline.

More than 2.3 million people have a diagnosis of MS worldwide, according to the National Multiple Sclerosis Society. Nearly 1 million people over the age of 18 live with a diagnosis of MS in the US, the nonprofit organization adds.

Applegate won her Emmy in 2003 for a guest spot on “Friends” and has a Tony Award nomination for the musical “Sweet Charity.” Her films include “The Sweetest Thing,” “Anchorman,” “Hall Pass” and “Bad Moms.”