Actress Erin Moran, who played Joanie Cunningham on the hit TV series Happy Days died on 22 April. She was 56 years old.

Her body was found in Indiana following a call about an "unresponsive female". The cause of her death is not known.

"[The 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," a statement from the sheriff's department in Harrison County, Indiana, said.

Moran's Happy Days co-stars Henry Winkler, Ron Howard and others took to Twitter to pay their respects to the late actress.

"OH Erin, now you will finally have the peace you wanted so badly here on earth, Rest In It serenely now, too soon," Winkler, who played Arthur 'Fonzie' Fonzarelli on the show, wrote on Twitter.

Howard, who played Richie Cunningham – on-screen big brother to Moran's character Joanie – said: "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."

After learning about Moran's demise, Anson Williams, who played Warren "Potsie" Weber on the show told, ABC 7: "Erin was a person who made everyone around her feel better. She truly cared about others first, a true angel. I will miss her so much... she is in God's hands."

Moran was from Burbank, California and began her career in acting before she turned 10. She was cast for the role of Joanie Cunningham as a 14-year-old. The show aired from 1974 to 1984. She also reprised the role in a short-lived spinoff Joanie Loves Chachi in 1982 alongside Scott Baio.