ET recently caught up with the 69-year-old singer at a benefit concert hosted by Kevin Costner to help raise money for the recent Santa Barbara, California, wildfires, where she gave us an update on her health. Newton-John was first diagnosed with the disease in 1992, and again in May 2017.
"I've been great," Newton-John, who also performed at the event, told ET's Keltie Knight. "Yeah, I feel really good."
Despite her battle with cancer, Newton-John said she wanted to show up and help the victims of the Thomas Fire, a blaze that destroyed more than 1,000 structures and scorched more than 281,893 acres last December.
"I feel so fortunate to have had the success I've had, and to do the wonderful things I do," she explained. "And to give back -- I'd love to be able to do that."
Newton-John did just that by taking the stage to perform a few hit songs from Grease, including "You're the One That I Want" and "Summer Nights." This year marks the film's 40th anniversary, and the blond beauty says it was nice to celebrate with such a great crowd.
"They're amazing," she said of the 5,000+ guests in attendance. "They sang every song. They were lovely. The were very warm and very receptive."
Last September, Newton-John said in an interview with Australia's 60 Minutes that her second battle with breast cancer was "agonizing," as it left her unable to walk for a few weeks. She underwent herbal and photon radiation therapies and was using medical marijuana grown by her husband, John, to cope with the pain.
"I need to get through this," she declared at the time. "I have lots to do, but of course, it's scary. I'd be lying if I said it wasn't scary. It was, but I felt very sure that I would get through."
She gave another update while chatting with ET last August. Hear more from that interview in the video below.