The 'Grease' star died on Monday after a decades-long battle with breast cancer.
Olivia Newton-John will be remembered as a "sweetheart" who was truly selfless until the very end.
GRAMMY-winning singer Dionne Warwick and TV/radio personality Leeza Gibbons, two of Newton-John's closest friends, spoke to ET's Kevin Frazier and offered a glimpse of the special bond they shared with the Grease star who died on Monday after a long battle with breast cancer. She was 73.
Warwick tells ET they first met in England when Newton-John was working on a show decades ago with the late singer Sacha Distel.
"We kind of just hit it off," the songstress recalled. "You know how girls are, and such a sweetheart. I mean, one of the nicest people I've ever met in a long, long time. She was Olivia. I think that was the charm that she never changed. She was Olivia."
Their friendship blossomed, and they'd appear together on Warwick's short-lived talk show, Dionne!, in 1990. Warwick recalled what made performing with Newton-John so special.
"It was two girlfriends on stage hanging out," Warwick recalled of the experience. "That's exactly what it was, and that's how I'm gonna always remember it, being around her and singing with her and being a part of her life, musically especially. She was very generous, very, when it came to performing with anyone. She kind of laid back when she needed to and gave it all she had when she had to. It was a lot of fun working with her. Very easy."
Not just that, Newton-John appeared on Warwick's 2006 album, My Friends & Me, teaming up for "Wishin' and Hopin'."
"You know, when you find songs that are as lovely as that and meaningful as that, it's very easy to sing," Warwick said of their duet.
Warwick recalled that when she told Newton-John about the project, she nearly fell out of her chair when Newton-John revealed "Wishin' and Hopin'" was her favorite song.
"Of all songs in the world," Warwick said. "But we had such a good time in the studio doing it. It was one of those songs that you kinda poke a little fun at, and she loved doing that. She was a kind person."
Warwick described Newton-John's voice as "crystal," and the acclaimed singer described exactly what that meant.
"Well, first of all, definitely clear," she explained. "Sweet. Enduring. That's what crystal is. It's something that will last forever.
As for Gibbons, she first met Newton-John when she interviewed the actress/singer in the 1980s as a correspondent for Entertainment Tonight.
"She had been one of my real inspirations and role models in high school growing up in South Carolina and I never imagined there'd be a time that I would A), meet her and B), become such dear friends with her. And from the get-go, she was Olivia, just this pure genuine heart."
They became so close, Gibbons says Newton-John asked her in 2008 to walk the Great Wall of China with her as part of a project for Newton-John's Cancer Wellness & Research Center, which the actress established in Australia, where she grew up since she was 5 years old.
"She had just gotten married to John Easterling, the love of her life. I had just gotten divorced. My mother had died. I was in a very dark, low place and Olivia was such an important example for me of hope," Gibbons recalled. "She always said to me, 'Leeza, keep your heart open and be gentle with yourself.' So, we bonded in a way that I think Olivia does with many people, she is just like this fountain of caring and love, and she just shows up for her friends as she did for me time and time and time again."
Gibbons revealed that it was around five years ago when she noticed things were no longer the same for Newton-John.
"I had a birthday dinner and Olivia was to join me for that five years ago," she said. "She called me and she said, 'I'm in so much pain I have sciatica. And at that moment my heart sunk, 'cause I went, 'Oh, no.' And right after that, we realized it was the recurrence of her cancer. So, I think there's been increased focus for the past few years."
Gibbons perfectly captured what it was about Newton-John that made so many easily fall for her.
"Whether you were a Hollywood star or a dignitary or those cancer patients that were so important to her, Olivia was the 'it' girl," she explained. "Yes, she was a Dame and yes she was America's sweetheart and the global celebrity that she was, but she just had that intangible 'it' factor that just attracted people to her. I think it was her light, and that light will never dim."
And, for the new kids on the block, Gibbons makes an apt comparison to those just now discovering Newton-John's endless talents.
"She was Madonna. She was Taylor Swift," Gibbons said. "Everything she did turned to gold. She builds success upon success upon success. Olivia was this multimedia icon before we even really knew what that was, way before there were social media to push it along."
Despite all of her success and in spite of her suffering amid cancer, Gibbons says Newton-John cared deeply for all and through it all.
"For people who loved her and knew her on an intimate level, there were big grand successes and then there were the small acts of caring that were really Olivia at her finest," Gibbons said. "She never talked about herself, she never bragged on her accomplishments, she never wanted to talk about her illness. She would quickly turn it around and engage others around her. That’s what fed her."
"I think, in the end, she got everything that she wanted in her life," Gibbons continued. "She got her happily ever after with John, she got her close relationship with the light of her life, her daughter Chloe. She got her legacy in cancer wellness and prevention and plant medicine, and she got to live out her final days in relative seclusion in the ranch that she loved so much with all of her animals and her dogs and just, the place that made her feel most at home."
Gibbons said she and her husband, Steven Fenton, spent a weekend with Newton-John not too long ago, and her radiance and optimism, perhaps to no one's surprise, was still very much on full display.
"She was very loyal to so many in her life, and the phone calls started coming in and the tears started flowing," Gibbons said. "It was the moment we all thought would never happen because Olivia seemed to be immortal. We thought she would beat this thing for so long, for decades, that she could just beat it again. But, it was time, and I think she got her life in order exactly the way she wanted it -- peace, integrity, dignity, love."
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