Erin Moran, a former child actor who rose to fame as Joanie Cunningham on "Happy Days" and its short-lived spinoff "Joanie Loves Chachi," has passed away at age 56.

CNN reports her body was found Saturday afternoon by the Harrison County (Indiana) Sheriff’s Department, which had received a 911 call about "an unresponsive female." An autopsy is pending.

Born on Oct. 18, 1960, in Burbank, California, and raised in North Hollywood, Moran began acting at age 5, with roles on such television shows as "Daktari," "Death Valley Days," "Family Affair" and Gunsmoke." At age 12 the was cast as Joanie, the mischievous kid sister of Ron Howard's Ritchie Cunningham on the popular sitcom "Happy Days."

Moran grew up over the course of the comedy's decade-long run, from 1974 to 1984, with Joanie becoming a central character and her relationship with Scott Baio's Chachi Arcola a major storyline. In 1982 the two even starred in their own "Happy Days" spinoff, "Joanie Loves Chachi," which lasted for just 17 episodes.

With the end of "Happy Days," Moran's acting career sputtered to a halt, with the actress landing only a handful of guest roles. She left Hollywood in the mid-1980s, first for the California mountains and then later, with second husband Steve Fleischmann, Indiana. Moran's last television credit is listed as an appearance as herself on a 2012 episode of "Celebrity Ghost Stories."

Moran's "Happy Days" co-stars responded on Twitter to news of her death, with Howard writing, "I'll always choose to remember you on our show making scenes better, getting laughs and lighting up tv screens." Henry Winkler, who shot to stardom as Fonzie, tweeted, "OH Erin... now you will finally have the peace you wanted so badly here on earth."

So incredibly sad to hear about Erin. A wonderful, sweet, caring, talented woman.I can't really comprehend this right now.Very painful loss— Don Most (@most_don) April 23, 2017

OH Erin... now you will finally have the peace you wanted so badly here on earth ...Rest In It serenely now.. too soon— Henry Winkler (@hwinkler4real) April 23, 2017

Such sad sad news. RIP Erin. I'll always choose to remember you on our show making scenes better, getting laughs and lighting up tv screens. https://t.co/8HmdL0JKlf— Ron Howard (@RealRonHoward) April 23, 2017