Former Happy Days actors Ron Howard and Henry Winkler have led tributes to their co-star Erin Moran, who has died at the age of 56.

Erin played Joanie Cunningham in the hit sitcom as well as its spin-off Joanie Loves Chachi.

 Erin Moran of the television show, "Happy Days" in Los Angeles
Erin Moran in 1982 (Wally Fong/PA)

Ron, who played her older brother Richie Cunningham but is now a film director responsible for blockbusters including Apollo 13 and The Da Vinci Code, wrote on Twitter:

Henry, who is best remembered as Happy Days heartthrob Arthur “The Fonz” Fonzarelli, wrote:

The sheriff’s department in Harrison County, Indiana, said a dispatcher “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.”

Erin joined the Happy Days cast in 1974 when she was 13 and in 2009 she told Xfinity: “What happened with all of us was like we were this family.

“It was so surreal with all the cast members … They were my family, get it?”

The actress also appeared in The Love Boat, Murder, She Wrote, The Waltons and Diagnosis Murder.

In 2012, she received a settlement from US network CBS after joining various Happy Days cast members in a legal action claiming they were owed money from merchandising revenue.