The actor who played Charlie's mother in "It's Always Sunny in Philadelphia" and starred in "Pee-wee's Playhouse" died at age 78 on Friday, a spokesperson for the actress confirmed to CBS News.

She was the “most beautiful woman in Puppetland” in the 1980s children’s show starring Paul Reubens, and more recently had a recurring role in “It’s Always Sunny in Philadelphia.”

Lynne Marie Stewart, who is known as Miss Yvonne on Pee-wee’s Playhouse and Bonnie Kelly on It’s Always Sunny in Philadelphia, died Friday. She was 78. The cause of death has not been disclosed.