Olivia Newton-John has died at 73 at her home in California after a long battle with cancer, her husband says.

The Australia singer and actress who starred in Grease and had a series of hit songs in the 1970s and 80s had battled breast cancer for decades.

Her husband John Easterling said on Facebook: "Dame Olivia Newton-John (73) passed away peacefully at her Ranch in Southern California this morning, surrounded by family and friends. We ask that everyone please respect the family's privacy during this very difficult time.

"Olivia has been a symbol of triumphs and hope for over 30 years sharing her journey with breast cancer. Her healing inspiration and pioneering experience with plant medicine continues with the Olivia Newton-John Foundation Fund, dedicated to researching plant medicine and cancer. In lieu of flowers, the family asks that any donations be made in her memory to the Olivia Newton-John Foundation Fund.

"Olivia is survived by her husband John Easterling; daughter Chloe Lattanzi; sister Sarah Newton-John; brother Toby Newton-John; nieces and nephews Tottie, Fiona and Brett Goldsmith; Emerson, Charlie, Zac, Jeremy, Randall, and Pierz Newton-John; Jude Newton-Stock, Layla Lee; Kira and Tasha Edelstein; and Brin and Valerie Hall."

Her Grease co-star John Travolta said: "My dearest Olivia, you made all of our lives so much better. Your impact was incredible. I love you so much. We will see you down the road and we will all be together again. Yours from the moment I saw you and forever!
Your Danny, your John!"

Newton-John has battled breast cancer for more than 30 years. A source told TMZ, "After a 30-year cancer journey, she lost her battle to metastatic breast cancer."

The Australian actor starred in Grease with John Travolta.

The star had hit songs If Not for You in 1971 and Let Me Be There in 1973.

But her big break came in 1978 when she starred as Sandy opposite John Travolta in Grease, belting out songs including You're the One that I Want, Summer Nights and Hopelessly Devoted to You.

Her biggest hit was Physical in 1981, which was at number one in the US charts for 10 weeks, breaking records in the 1980s.

Olivia Newton-John with daughter Chloe Lattanzi and husband John Easterling in 2019. Photo / Getty Images

Newton-John was born in Britain but raised in Australia. She met husband-to-be Matt Lattanzi on the set of Xanadu and they married in 1984, having daughter Chloe Rose in 1986. The couple divorced in 1995.

She married Easterling in 2008.