It's been 40 years since the single took over the airwaves. "Physical" was Newton-John's fifth No 1. single and the most successful song in her career, selling 10 million copies. But some radio and TV stations banned it for being too sexual.
"The things that are out there now! The things they talk about and say freak me out," Newton-John jokes to ET's Nischelle Turner, adding her song "is like a lullaby!"
"Physical" came out in September of 1981, but the Grease star admits she was hesitant about the song and even tried to stop it from being released.
"A dear friend of mine wrote the song and I thought, 'This is a great song!' And I recorded it with John Farrar, who's my producer and also my friend, and after it was finished, that's when I freaked out," she recalls. "I went, 'I never even thought about the double entendre here!' I called my manager and said, 'We have to, we have to kill it! Let's stop it because I think I've gone too far.' And he said, '[It's] already on the charts, doll. It's doing really well, we can't stop it.'"
"I'm finding that very often the things you are most afraid of or tentative about doing are the things you need to do," she acknowledges. "So I'm very thrilled that I didn't pull it off the charts."
Forty years for Newton-John "feels like yesterday and it feels like a century ago," but she couldn't be happier that artists like Dua Lipa and Doja Cat are sampling her music.
"I'm honored and the people still love the song 40 years later," she notes. "I'm thrilled for Stevie [Kipner] because he wrote it and I never dreamt in my life that 'Physical,' 40 years later, people would still be loving it. I feel very lucky."
A deluxe edition of "Physical" will be out Oct. 22. Newton-John also partnered with Crunch Fitness and Third Love to celebrate the 40th anniversary of her song to help raise funds and awareness for her Olivia Newton-John Foundation Fund. The goal of the physical challenge is to set a world record for the number of leg raises.
"I doubt I can even lift a leg now," the superstar jokes. "I think it's a fantastic idea of them trying to set a world record about how many people do it at the same time!"
Newton-John recently turned 73 and is living on her Santa Barbara ranch and focusing on her health after her cancer battle.
"I had breast cancer in '92 and I had a recurrence a few years ago, so I've been through chemotherapy and radiation and all things," she shares. "And my dream always was when going through those things, because it's difficult and they're not comfortable, was to try and find treatments that were kinder."
"And my husband, John, has been growing me cannabis for a long time and making me these tinctures," she adds. "And I think that's why I'm still here. I feel very fortunate. It helps with my pain, it helps a lot of things."