It was her fifth No 1. single off her 11th studio album of the same name and went certified platinum. Now, looking back, Newton-John told Fox News the song allowed her to "reinvent" her image from good girl to sultry siren.
"They call it reinventing yourself," she said of the shift in how she was perceived by fans after the song became a hit. "I wasn't doing it on purpose. It just was the song that I was attracted to and the album. But I feel very fortunate that I had the opportunity to record it."
At the time, back in September 1981, "Physical," was considered too scandalous for some markets and was banned from playing on some radio stations.
"I felt a little embarrassed to be banned," the "Grease" star admitted. "But looking back now I go, ‘That was great.’ It got attention. And also compared to what I'm listening to on the radio now, it's more like a lullaby."
Newton-John admitted the lyrics were a bit "raunchy" but "I don't think I was really aware of how raunchy it was when I was recording it until afterward, and that's when I freaked out."
The 73-year-old singer/actress recalled how "Physical" was originally written for Rod Stewart in mind and then later offered to Tina Turner who turned it down.
"I heard the song and I thought, 'Wow, that's a great song.' I didn't really realize what it was about. I don't think until I'd finished it and then freaked out," she said. "[I thought then] 'I think I've gone too far, I think I've gone too far.' But it worked for me, so I'm very happy that I took the chance."
A deluxe edition of "Physical" will be out Oct. 22. To celebrate, Newton-John has partnered with Crunch Fitness and Third Love for a Guinness World Record attempt and TikTok "Physical" challenge to raise awareness for her foundation and plant medicine research to find kinder ways to treat cancer. The goal is to set a world record for the number of people doing the famous leg lift from the "Physical" music video.
Newton-John also spoke about her ongoing battle with cancer and how she's feeling today.
"I feel very fortunate that I'm here," she told Fox. "And you know, I have my days. I take a lot of cannabis and that really helps me greatly. My husband grows it for me and it helps me with pain and sleep and inflammation."
She said through her foundation, the Olivia Newton-John Foundation Fund, they're pursuing scientific research into how cannabis can provide relief for cancer patients.
"So my dream is that in my lifetime, we will find the answers," Newton-John added. "Because cannabis is not something that you can overdose on or die from, whereas a lot of the other drugs that you have to go through on your cancer journey are not safe. So that's my long-term dream."