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.

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.