The British-born singer died “peacefully” at her ranch in southern California on Monday morning, surrounded by family and friends, her widower confirmed.
After the news broke, famous names from the worlds of television, film and music took to social media to share memories and send condolences to her family.
Veteran singer Sir Elton shared a collection of photos of him and Dame Olivia together on Instagram as he remembered his “warm and loving friend”.
He wrote: “The saddest of news to wake up to. Olivia was a beautiful and courageous woman, who I never heard complain about her illness.
“A beautiful voice and a warm and loving friend. I will miss her so much. Condolences to her family and loved ones.”
Pop titan Carey recalled the “moment she will never, ever forget” when she got to perform Hopelessly Devoted To You alongside the Grease star in Melbourne, Australia.
She said she first “fell in love” with Dame Olivia’s voice as a child and felt “blessed” to be in her presence on many occasions.
Alongside a selection of photos of them performing together, the singer described her as “the kindest, most generous and lovely person she had ever met”.
Sir Rod Stewart hailed his “great friend” as the “perfect lady”, adding that she was “gorgeous, with great poise and with a certain Aussie sophistication”.
The singer also revealed that her black spandex trousers in the classic last scene of 1978’s Grease were the inspiration behind his style in his Da Ya Think I’m Sexy? track released in the same year.
Oprah Winfrey recalled a dinner she had with Dame Olivia in 2019, remarking on how her positive outlook on her cancer diagnosis was “infectious”.
Pop megastar Kylie Minogue said Dame Olivia “was and always will be” an inspiration to her.
“Since I was ten years old, I have loved and looked up to Olivia Newton John,” the singer wrote on Twitter.
“And, I always will. (Just like this picture @nfsaonline) She was, and always will be, an inspiration to me in so many, many ways.
“My deepest condolences to her family and loved ones. x ONJ4EVER.”
Sharing a picture of the pair together, Peter Andre hailed her as “a true icon” who was “warm, kind and caring to everyone”.
“I will never forget this night. I had the privilege of performing alongside Olivia Newton John for the Spina Bifida charity concert in Australia,” he said.
“She was warm, kind and caring to everyone backstage. She was the same every time we met.
“A true icon. Sad day.”
Nancy Sinatra said although she had not known Dame Olivia personally, she had admired her for “the way she faced her health battles”.
“Beautiful & strong, she fought to the end,” she wrote.
“My heart goes out to her family & all who love her. It’s just not fair.
“Godspeed, Olivia. We’ll always be hopelessly devoted to you.”
Dionne Warwick, who recorded a duet with Newton-John in 2006, tweeted: “Another angelic voice has been added to the Heavenly Choir.
“Not only was Olivia a dear friend, but one of the nicest people I had the pleasure of recording and performing with. I will most definitely miss her.
“She now Rests in the Arms of the Heavenly Father.”
US singer Richard Marx, who also duetted with Dame Olivia, said he would “miss her every day”.
“My heart is broken. Rest now, sweet friend,” he wrote on Twitter.
“You were as kind and loving a person as there’s ever been. I’ll miss you every day.”
Oscar-winning actress Marlee Matlin recalled starring alongside Dame Olivia in the 1996 film It’s My Party, one of the first films to address the topic of Aids patients dying with dignity.
She said on Twitter: “I am SO saddened at the news of the passing of Olivia Newton John.
“I remember being so star struck when I met her at my first Hollywood gathering for Paramount.
“She was the sweetest and brightest light and I loved getting to know her on It’s My Party. RIP dear, sweet Olivia.”
British actor Sanjeev Bhaskar recalled the actress’s kindness during a brief encounter many years prior.
“Ah so sad. I met Olivia Newton John once many years ago. In that 5 min chat I felt like I’d been blessed,” he said.
“She didn’t know me from a pumpkin but was so warm, interested and charming. I was hopelessly devoted to her all over again.”
Hollywood star Antonio Banderas tweeted: “Rest in peace, Olivia Newton-John. Deepest condolences to her family and loved ones.”
American filmmaker and actor James Gunn called her his “first real crush” and revealed he previously bought her home in Malibu.
“Really sad to hear about the passing of Olivia Newton-John,” he tweeted.
“My first real crush as a kid.
“I loved Grease & her music & I coincidentally also bought & lived in for a while the wonderful home she built in Malibu. May she Rest In Peace.”
US actress Rosanna Arquette, who won a best supporting actress Bafta for her performance in 1985’s Desperately Seeking Susan, was also among those paying tribute.
She tweeted: “Fly with the angels Olivia Newton John.”
Filmmaker Edgar Wright, whose credits include Last Night In Soho and Baby Driver, tweeted: “Olivia Newton John so completely dominated the charts and Top Of The Pops when I was a kid, it felt like she WAS pop music.
“And yes, Xanadu is still a stone cold classic song. RIP.”
Kiss co-founder and frontman Paul Stanley said: “So very sad. She was everyone’s sweetheart.”