Erin Moran, Joanie Cunningham In "Happy Days," Dies At 56

NEW YORK (WWJ/AP) - Erin Moran, the former child star who played Joanie Cunningham in the sitcoms "Happy Days" and "Joanie Loves Chachi," has died.

Police in Harrison County, Indiana, said that she had been found unresponsive Saturday after authorities received a 911 call. She was 56, and the cause of death has not been determined. Moran had endured numerous struggles in recent years.

Moran was already a veteran actress when in 1974 she was cast in "Happy Days" as Joanie, the kid sister to Ron Howard's Richie Cunningham in the sitcom set in the 1950s. She would later appear with Scott Baio in the "Happy Days" spinoff "Joanie Loves Chachi."

Howard took to Twitter to share thoughts of his on-screen little sister:

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)