Australian singer Helen Reddy has died in Los Angeles, aged 78.

Reddy, who became a global superstar on the back of her smash hit I am woman, was diagnosed with dementia in 2015.

She died on Tuesday (local time).

Reddy’s death was confirmed on her official Facebook fan page by her daughter Traci and son Jordan on Wednesday morning (Australian time).

“It is with deep sadness that we announce the passing of our beloved mother, Helen Reddy, on the afternoon of September 29th, 2020, in Los Angeles,” they wrote.

“She was a wonderful mother, grandmother and a truly formidable woman. Our hearts are broken. But we take comfort in the knowledge that her voice will live on forever.”

Reddy was born in a show business family in Melbourne in 1941. She started singing on radio and TV aged just four.

In 1986, a prize from a TV show – a ticket to New York and a record audition – was her gateway to the US. The audition was unsuccessful, but Reddy stayed on in Chicago and then Los Angeles.

Her 1970 B-side single, I don’t know how to love him, became a Canadian top 10 hit and she quickly signed a record deal.

US top 10 hits followed, before I am woman in 1972. It became a feminist anthem and earned her a Grammy award – the first Australian to do so.

“I think it came along at the right time. I’d gotten involved in the women’s movement, and there were a lot of songs on the radio about being weak and being dainty and all those sort of things,” Reddy said 30 years later.

“All the women in my family, they were strong women. They worked. They lived through the Depression and a world war, and they were just strong women. I certainly didn’t see myself as being dainty.”

She married Kenneth Weate, an older musician and family friend, when she was just 20. The couple separated not long after the birth of their daughter, Traci.

In 1968, Reddy married her manager, Jeff Wald. The couple’s son, Jordan, was born in 1972.

After a troubled marriage, they divorced in 1983. Jordan, who later changed his name to Sommers, posted his own tribute to his mother on Wednesday – a picture with Reddy and his sister.

Reddy had lived in California for several years near her children. She last toured Australia in 2014.

A biopic about her life, which has the same name as biggest hit, premiered at the Toronto International Film Festival in 2019.

Reddy’s fans from around the world quickly flooded her fan page with praise for her achievements and sharing their grief at her death.

“Quiet please, there is a lady leaving the stage,” the page administrator posted.