The actress known for playing the stunning 'Sandy' in Grease alongside John Travolta.
John Travolta who co starred alongside Newton-John in the hit musical, called her impact "incredible" and added that she "made our lives so much better".
"My dearest Olivia, you made all of our lives so much better", he said. "Your impact was incredible. I love you so much".
"We will see you down the road and we will all be together again", she added. "Yours from the first moment I saw you and forever!".
"Your Danny, your John!".
Also among these tributes, global megastar Kylie Minogue wrote that Olivia will "always be" an inspiration to her.
"Since I was ten years old, I have loved and looked up to Olivia Newton John", Minogue said. "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".
Peter Andre also paid an emotional tribute to Olivia Newton John via social media. Hailing her as "warm and kind to everyone" and a "true icon", he added, "I will never forget this night. I had the privilege of performing alongside Olivia Newton John for the Spina Bifida charity concert in Australia".
While she may not have known her personally, Nancy Sinatra admired Olivia for "the way she faced her health battles".
Olivia Newton John was 73 years old. She died peacefully in her Southern Californian ranch, surrounded by family and friends. Newton-John had previously battled cancer twice.
