LONDON (Reuters) - With a range spanning the cardigan-clad sweetheart in the hit musical "Grease" and the leotarded gym instructor in the raunchy single "Physical", no one could accuse Olivia Newton-John of playing it safe in 40 years of singing country, pop and rock.
The Australian, who was born in England and is touring there for the first time in 35 years, admits to being terrified at some of the choices she made in a career boasting four Grammy awards and a lead role in the biggest musical movie hit in U.S. history.
"I like a challenge," Newton-John, 64, told Reuters in an interview before starting a six-concert tour that ends on March 17 in Manchester.
"I was always afraid of these changes but I did them anyway, kind of 'face your fears' ... because I felt you also had to challenge yourself a little bit. But I was terrified."
The 1981 release of "Physical", a song from the album of the same name, was banned by some radio stations in the United States banned for raunchy lyrics such as "There's nothing left to talk about/Unless it's horizontally."
"I remember calling (manager) Roger Davies right after I'd finished it ... and going 'Oh, I'm not sure we should put this out, it's a little too risqué'. He said: 'It's too late, love, it's gone to radio'."
Adding to the controversy was the video, in which Newton-John played a gym instructor in a tight leotard surrounded by oiled body-builders portrayed as gay in a twist ending.
"I look back now and it's hilarious, because that was so naughty in its time," she recalled. "That was another challenge that worked, thank goodness. It was either going to be a big success or nothing. There was no in-between with that song.
"It was banned in Utah and I did my television special for the Physical Tour in Utah. I remember I was probably so terrified I got sick right before the shoot."
In fact, "Physical" proved to be the pinnacle of Newton-John's solo career, topping the U.S. pop charts and becoming one of the best-selling singles of the decade.
By then, Newton-John had already left her comfort zone more than once. She recalled pursuing a career as a performer despite resistance from her parents, who wanted her to finish school.
She comes from an academic background - her grandfather was Max Born, a German-British Nobel Prize-winning quantum physicist.
"My grandfather apparently used to play music with Einstein, they used to play chamber music together, so it (the musical gene) goes back," Newton-John said.
She left Australia for Britain in the 60s to make it as a pop star. By the early 70s, she had featured in the charts and on television before representing the United Kingdom at the 1974 Eurovision Song Contest, finishing fourth behind winners ABBA.
Then came a move to the United States, where Newton-John broke into the country music scene despite being considered an outsider. Her hit "Let Me Be There" won her a country vocal Grammy.
The next gamble came with "Grease", the hit 1978 film adaptation of the Broadway musical that would turn her into a household name.
"Grease itself was a bold enough move - playing the second character in Grease, and for that to be so successful, I mean, who knew?"
Her character's transformation from clean-cut "Sandy 1" to spandex-clad "Sandy 2", out to snare John Travolta's Danny, was one that she took into real life, ditching the safety of soft pop and country for an edgier image and sound.
The name of her next album? "Totally Hot".
"The raunchy kind of image that Sandy 2 had, it gave an opportunity to change my direction a little bit and do something a little more fun," she said.
"I did country, and then it was pop, and then 'Grease' kind of went into rock and so I got to change a little bit. Everyone does it now, but then it probably wasn't so common."
Newton-John, now based on the west coast of the United States along with her family including daughter Chloe, said she would continue to record new music but may cut back on touring.
"I have so many ... other things I'm passionate about and involved in and I love singing and I love recording, but touring takes a toll and you're away from home a lot," she explained.
Newton-John, who survived breast cancer in 1992, has set up a cancer centre in Australia and has campaigned on issues including deforestation, dolphin culling and fracking.
Why does she take on so many issues outside music?
"I think it's really for my mum," she said. "My mum was always writing letters to the council about problems, and so I think I owe that to her."
Reporting by Mike Collett-White; Editing by Kevin Liffey