LOS ANGELES • Olivia Newton-john, the beloved singer and actor known for her 1970s and ’80s hits and the movie “Grease,” died at her ranch in Southern California on Monday at age 73.

A cause of death hasn’t been announced, but she was diagnosed with breast cancer in 1992 and underwent years of treatment. The cancer returned in 2017.

“Olivia has been a symbol of triumphs and hope for over 30 years sharing her journey with breast cancer,” her husband, John Easterling, wrote Monday on the singer’s official Facebook page to announce her death. “Her healing inspiration and pioneering experience with plant medicine continues with the Olivia Newton-john Foundation Fund, dedicated to researching plant medicine and cancer.”

Easterling said that she was surrounded by family and friends when she died.

Born in Britain in 1948, the youngest of three children, Newton-john moved to Australia when she was 5 and started singing at 12. She won a singing contest in 1964 that had a ticket to London as a prize. There, she cut her first single and became a fixture on the music scene. She made her first record, “If Not for You,” which put a song on the Top 25 in the United States after it came out in 1971.

Then Newton-john found herself in Los Angeles.

She broke onto the U.S. country music scene in the early 1970s, winning the Academy of Country Music honor for new female vocalist in 1973. Once her career took off, it was — for nearly a decade — unstoppable.

The Grammys came quickly. She won female country vocal performance for “Let Me Be There” in 1974 and pop vocal performance and record of the year for “I Honestly Love You” in 1975. The latter hit No. 1 on Billboard’s Hot 100 that year, ahead of “Have You Never Been Mellow” that year.

And Newton-john was beautiful. Still, despite her success and her rabid fan base, many critics took shots at her singing, saying she had no range and was just “another pretty voice.”

“Olivia Newton-john is often accused of having a very unsubstantial voice and only one asset — beauty,” Dennis Hunt wrote in a 1976 Los Angeles Times review of her show at the Greek Theatre. Then he went against the norm. “It is easy to form this opinion from listening to her records but it is not possible to cling to it after seeing her in concert.”

Other stories mentioned a need for more security when she played in Las Vegas if “the men in the audience get any more enthusiastic” than they were at one midnight show.

There was also the “nice” thing. The “innocent” thing.

“The only nasty thing people can find to say about N-J is that she’s too nice,” the Los Angeles Times wrote in 1977 while Newton-john was in production on her first big-budget feature film. “Her Sandra Dee-ish part in ‘Grease’ ... will do nothing to change her goody image.”

But the movie musical did include a notable image overhaul. It opened in 1978, featuring John Travolta’s bad boy Danny paired with Newton-john’s good girl Sandy, who by the end of the movie found herself reborn as a bad girl wearing full makeup, permed hair and black, skintight silk pants. The singer herself emerged emboldened.

It was peak Olivia.