Erin Moran, the former child star who played Joanie Cunningham in the sitcoms “Happy Days” and “Joanie Loves Chachi,” died Saturday at 56.

Authorities in Indiana said "received a 911 call about an unresponsive female. Upon arrival of first responders, it was determined that Erin Moran Fleischmann was deceased. An autopsy is pending."

The Harrison County dispatcher told the AP that the woman was an actress, who had been married to Steven Fleischmann.

A Burbank, Calif. native, Moran began acting in TV and movies before she was 10 years old. She had nearly a decade's worth of experience when she was cast in 1974 in "Happy Days" as Joanie Cunningham, the kid sister to high school student Richie Cunningham, played by Ron Howard.

Debuting at a time of nostalgia for the seemingly innocent 1950s, the sitcom was set in Milwaukee and soon became a hit. Howard and Henry Winkler, who played tough guy Arthur "The Fonz" Fonzarelli, were the show's biggest stars, but Moran also became popular. In 1982, she was paired off with fellow "Happy Days" performer Scott Baio in the short-lived "Joanie Loves Chachi."

Her more recent credits included "The Love Boat" and "Murder, She Wrote," but she never approached the success of "Happy Days" and was more often in the news for her numerous personal struggles.

Winkler tweeted his condolences late Saturday.

The Associated Press contributed to this report.