Olivia Newton-John, one of the biggest pop stars in the 1970s and early 1980s, has died at the age of 73. She died on Monday at her ranch in southern California, according to her husband, John Easterling, in a post on her official Facebook page. "Olivia has been a symbol of triumphs and hope for over 30 years sharing her journey with breast cancer," it reads in part.

In the 1978 movie musical Grease, Newton-John starred as the good girl Sandy Olson, who falls for a bad boy played by John Travolta, who had also played the role on Broadway. He lobbied hard for Newton-John to make her film debut as his costar.

"I wanted this girl bad," Travolta told Merv Griffin on TV in 1981. "The perfect Sandy, the ultimate Sandy, would be Olivia Newton-John."

But the 28-year old Australian singer was skeptical about playing a high school student.

"I couldn't do an American accent, and I was too old," she told the Today show in 2019. "And I had all these reasons why I couldn't do it. We did a screen test. The chemistry was there. It worked and when John came to see me at my house — how could you say no to John Travolta?"

No one, it seemed, could say no to Grease. The soundtrack was wildly successful. A duet with Travolta ended up as a best-selling single.

Newton-John was born in England in 1948. She grew up in Australia, and started her performing career as a teenager. A regular on local radio and TV shows, she won a talent contest and ended up recording country-pop songs in the U.S.

For "Let me Be There," she won her first Grammy award in 1973. The following year, she earned two Grammys for "I Honestly Love You." Mellow pop songs became Newton-John's stock in trade, but she won her fourth Grammy in 1982 for the suggestive single "Let's Get Physical."

The song made her uncomfortable, Newton-John told NPR in 2012. "I thought it was a great song, but then had a panic attack and called my manager and said, 'You can't put this out, it's too over the top and it's too risque,' " she said, only to learn it had already gone to the radio.

It was Newton-John's idea to make the video for the song about exercise, she said, and she wore a sweatband, leotards and legwarmers.

After her other hits – such as "Magic" — and other movies, such as Xanadu, Newton-John dropped out of the spotlight to raise her daughter, and promote causes such as environmentalism and breast cancer awareness, after she was diagnosed with the disease. She treated it, she said, with alternative therapies, medical marijuana, humor and optimism.