US actress Christina Applegate has revealed she has been diagnosed with multiple sclerosis (MS).
Applegate first found fame as a child actress on US sitcom Married... With Children and won an Emmy for playing Rachel's sister Amy in Friends.
"It's been a strange journey. But I have been so supported by people that I know who also have this condition," Applegate tweeted on Tuesday.
She asked for "privacy" as "I go through this thing".
The Dead To Me actress added: "It's been a tough road. But as we all know, the road keeps on going. Unless [someone] tries to block it."
Applegate, 49, has won plaudits for her TV acting roles including the title roles in sitcom Jesse (1998 - 2000) and comedy Samantha Who? (2007 - 2009).
Her performance in Dead To Me has seen her nominated for Golden Globe, Emmy, Screen Actors Guild and Critics' Choice awards.
She won a Primetime Emmy for her guest appearance as Rachel's sister in Friends in two episodes in 2002 and 2003.
Applegate was also a member of the original Pussycat Dolls, when they were a burlesque troupe.
Her film roles include Anchorman: The Legend of Ron Burgandy. She later reprised her role as Veronica Corningstone in Anchorman 2: The Legend Continues.
Applegate's other big screen outings include Bad Moms and The Sweetest Thing, opposite Cameron Diaz. She has also appeared on Broadway in shows such as Sweet Charity.