Erin Moran

Moran was found dead in her home in New Salisbury on Saturday, authorities said.

"A subsequent autopsy revealed that Mrs. Moran likely succumbed to complications of Stage 4 cancer," the statement said.

Standard toxicology tests were performed and the results are pending, the statement said, but no illegal narcotics were found at Moran's residence.

Moran was best-known for her role as Joanie Cunningham, the younger sister of Richie Cunningham, who was played by Ron Howard, a child actor who is now a famed director.

Moran joined the Happy Days cast in 1974 when she was 13.

She also made appearances in Murder She Wrote and The Waltons.

In recent years, she was reported to be living in an Indiana trailer park.

In 2010, she joined various Happy Days co-stars in filing a lawsuit against television network CBS, claiming they were owed money from merchandising revenues.

The suit was settled in 2012, with the actors each receiving a payout of $65,000 (£50,000).

They originally asked for $10 million.