Born: September 26, 1948;

Died: August 8, 2022.

Olivia Newton-John, who has died from cancer at the age of 73, was a singer who was one of the world’s most commercially successful recording artists ever, with more than 100 million sales to her credit, but she was associated above all with her leading role in the film of the musical Grease.

In 1978, Grease was not only the biggest film, but the most commercially successful screen musical of all time – beating The Sound of Music’s record, which it then held until 2017’s live-action remake of Beauty and the Beast – and it retained its popularity in subsequent decades, going on to gross more than $400 million. In 2004, a Channel 4 poll selected it as the greatest musical ever.

Newton-John’s role as Sandy Olsson, a high school goody-two-shoes who transforms herself into a vamp to win the heart of John Travolta’s Danny Zuko, also gave her two songs that reached, and stayed at the top of, the charts.

Hopelessly Devoted to You (nominated for an Academy Award as Best Original Song) and You’re the One That I Want (which spent nine weeks at No 1, and is one of the highest-selling singles in British chart history, were both especially written for her, and had not featured in the original stage show.

But though Grease was an unprecedented phenomenon, Newton-John had enjoyed a stellar career before it: she had had seven consecutive number one records in the American “Adult Contemporary” charts and numerous hits on the pop and country charts, including five consecutive gold singles in the top ten of the Billboard Hot 100. She had represented the UK at the Eurovision Song Contest in 1974 with Long Live Love.

Though she later admitted she didn’t think much of the song, it came fourth; the winner was Waterloo, by an unknown group from Sweden called Abba. And when she released her Greatest Hits in 1977, its sales were certified as platinum before Grease had even been filmed.

There were highlights after Grease as well. Her single, Physical, reached the UK Top Ten (peaking at No 7), but in America, it was No 1 on the Billboard Hot 100 for a record ten weeks. Recorded in January 1981, it was later listed as the USA’s most successful single of the decade, while the album of the same name went double platinum.

Olivia Newton-John was born in Cambridge on September 26, 1948, the daughter of a Welsh headmaster and former officer in MI5. Brin Newton-John, a German scholar, had worked on the Enigma project at Bletchley Park and been one of the officers who authenticated the identity of Rudolf Hess after the Deputy Führer’s failed secret flight to see the Duke of Hamilton for peace talks in 1941. After the war, he became head of Cambridgeshire High School for Boys (now Hills Road Sixth Form College).

Olivia’s maternal ancestry was even more academically distinguished; her mother Irene’s father was Max Born, the Nobel laureate in physics who developed the field of quantum mechanics and, as a Jew, left Germany after the rise of Hitler. At the time of Brin and Irene’s marriage, he was Professor of Natural Philosophy at Edinburgh.

In 1954, the Newton-John family emigrated to Australia, where Brin became Master of Ormond College in the University of Melbourne, and a Professor of German. Olivia attended Christ Church Grammar School and the Melbourne’s University High School, where she became deeply involved in music and theatre. (Her father was a keen violinist and singer, especially of lieder, and lectured on music as well as German.)

Her parents divorced when she was ten. At 14, she joined an all-girl pop group, Sol Four; though it was not especially successful, she began to get solo work singing on local television and radio shows. There she met Pat Carroll, with whom she teamed up for duets, and John Farrar (whom Pat Carroll later married), the songwriter responsible for many of Newton-John’s biggest hits. Her big Australian break came on the talent show Sing, Sing, Sing, on which she won a trip to Britain.

She released her first single in 1966 and for a while made appearances with Pat Carroll as a duo, and in a group put together by one of the producers behind The Monkees. Her first solo album, If Not For You (1971), brought her hits in the USA, UK and Australia, and she became a frequent guest on Cliff Richard’s television show.

After Eurovision, she moved to America, where she had had little success until she branched into pop/country territory with Let Me Be There, for which she won a Grammy in 1973. Concentrating on that market, she had a string of hits in the late 1970s until, aged 28, she was cast as Sandy in Grease.

After Grease, she made a not entirely convincing attempt to be raunchier, with an album, Totally Hot, which featured her clad in leather; in 1980, she released I Can’t Help It, a duet with Andy Gibbs, and appeared in the disco musical Xanadu with Gene Kelly as an improbable co-star. Though the film was a flop – so bad, indeed, that it never even acquired cult status for its camp dreadfulness – the soundtrack was a huge hit, with the title track (with the Electric Light Orchestra) reaching No 1. Suddenly (with Cliff Richard) and Magic were more modest British chart hits, though the latter became a No 1 hit in America.

She continued to turn out records, especially Christmas albums, but though there were (including soundtracks and compilations) some two dozen discs released after Physical and the second volume of her Greatest Hits (1982), her heyday as a chart-topping act was over.

She set up a company called Koala Blue, which specialised in Australian products, and had a daughter in 1986 with her husband Matt Lattanzi, an actor she had met on the set of Xanadu and whom she married in 1984. She became an advocate for Unicef, environmental groups and – after being diagnosed with breast cancer in 1992 – health charities. She was for many years president of the Isle of Man Basking Shark Society.

She divorced in 1995. In 2008, she married John Easterling, who ran an alternative medicine company.

She made regular guest appearances on other people’s recordings and also kept busy with television programmes, judging reality shows and hosting a wildlife programme in Australia. There were a few unmemorable TV movies and residencies in Las Vegas; she toured the UK in 2013 and was about to embark on another tour in 2017 when she discovered, in May that year, that her breast cancer had returned and metastasized to her back.

In addition to her husband, she is survived by her daughter, Chloe Rose Lattanzi; her sister, Sarah Newton-John; and her brother, Toby.

Writing on Instagram, John Travolta, her co-star in Grease, said that her "impact was incredible".

"My dearest Olivia, you made all of our lives so much better," he wrote. "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 first moment I saw you and forever! Your Danny, your John!"