John Travolta has led tributes to Olivia Newton-John, who died aged 73 on Monday (08.08.22)

The 68-year-old actor wrote on Instagram: "My dearest Olivia, you made all of our lives so much better.

"Your impact was incredible. I love you so much. We will see you down the road and we will all be together again. Yours from the first moment I saw you and forever! Your Danny, your John!"

Randal Keiser, who directed the high school classic, praised her for being "one of a kind, and so very kind".

He told the Hollywood Reporter: "I'm Heartbroken. She was one of a kind, and so very kind. For over four decades of our friendship she exuded nothing but love to everyone she met. Olivia was exactly the way you imagined her. I will miss her forever."

George Takei lamented that Hollywood "lost a great, iconic artist" with her passing.

He wrote on Twitter: "We have lost a great, iconic artist in Olivia Newton John, gone too soon from us at age 73. I trust she is now in the great Xanadu beyond. Know that we are forever hopelessly devoted to you, Olivia. Rest in song and mirth."

Gabrielle Union shared how much 'Grease' meant to her and her sister and how much she loved 'Xanadu'.

She wrote on Twitter: "'Grease' is my #1 movie of all time and made me a lifelong Olivia Newton John fan. Me and my sister watched Xanadu more times than I could count. Sending so much love and prayers to a real gift of a woman and talent."

Motown legend Dionne Warwick paid her respects to her "dear friend".

She 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."

Academy Award winner Marlee Matlin shared how she was "saddened" by the death of her 'It's My Party' co-star.

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."

Mia Farrow added: "Very sad that lovely, talented brave Olivia Newton-John has died. I never got to meet her, but everyone says she was wonderful - always kind."

Jane Lynch - who starred on 'Glee' where Olivia played a fictionalised version of herself in 2009 - tweeted: "ONJ. Angel".

'Guardians of the Galaxy' director James Gun revealed that the icon was his "first real crush".

He wrote on Twitter: "Really sad to hear about the passing of Olivia Newton-John. 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."

Broadcaster Katie Couric wrote: "Rest In Peace, Olivia."

TV chef Nigella Lawson tweeted: "Her memory is already a blessing."