John Travolta remembers 'Grease' co-star Olivia Newton-John: 'I love you so much'

Celebrities are paying tribute to Grammy-winning singer and actress Olivia Newton-John, best known for playing goody two-shoes Sandy in "Grease," who died following a long battle with breast cancer at 73 on Monday.

John Travolta honored his "Grease" costar on social media, appreciating her legacy.

"My dearest Olivia, you made all of our lives so much better," Travolta wrote in an Instagram post. "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!"

Olivia Newton-John dies at 73: Beloved 'Grease' star battled breast cancer

Hugh Jackman on Instagram paid tribute to Newton-John and called her his "first crush."

"It's no secret Olivia was my first crush," he recalled. "I kissed her (poster) every night before bed."

"I'm devastated to hear the news that @therealonj has passed away. One of the great privileges of my life was getting to know her. Not only was she one of the most talented people I've known … she was one of the most open-hearted, generous and funny. She was a one-of-a-kind spirit," Jackman wrote of the actress. "Her legacy will only grow stronger in the years to come. A fighter for healing from cancer that knows no bounds. I love you Olivia."

Newton-John's "It's My Party" co-star Marlee Matlin shared a photo of the 1996 film's cast on Twitter, writing she was "SO saddened at the news."

"I remember being so star-struck when I met her at my first Hollywood gathering for Paramount," Matlin wrote. "She was the sweetest and brightest light and I loved getting to know her on 'It's My Party.' RIP dear, sweet Olivia."

Actor George Takei honored the "great, iconic artist."

"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," Takei wrote.

British-American actress Jane Seymour shared a lengthy tribute Monday, writing she was "devastated to hear that my dear friend Olivia has passed."

"She was always a great friend and confidant to me. Olivia inspired everyone with her positive attitude to life and unfailing desire to help others," she wrote on Instagram. "I had the privilege of meeting her whilst living with her sister Rona when I first moved to the US. We became fast and lifelong friends. She was not only a brilliant musician, actress, and singer but a wonderful mother, wife, and sister.?"

Mariah Carey acknowledged Newton-John as "one of the kindest, most generous and lovely people I've ever met" in an Instagram post Tuesday.

"I first fell in love with Olivia's voice when I was a little girl and heard 'I Honestly Love You.' Songs like 'Magic,' 'Suddenly' and 'Have You Never Been Mellow' showcased her beautiful airy tone and signature sound," Carey wrote. "She will be missed. She will be remembered. She will be loved. Olivia, I honestly love you."

Kate Hudson honored Newton-John on Instagram by sharing a sweet video of her singing "Hopelessly Devoted to You" to her daughter Rani Rose.

"There are a handful of people in my life who inspired me to lock myself in my bedroom and sing from the top of my lungs in the mirror," Hudson captioned the video. "Mimicking every move she made, wishing I could hit those clean high notes and striving to try with my little rasp. What a lovely light of a human."

Hudson concluded: "She was an inspiration to me as I dreamed of what my performers life ahead may be. Thank you for sharing your light to the world as it moved and shaped little girls like me. May we all today sing for Olivia and celebrate her courageous years of fighting."

Robin Roberts took to Twitter to share her “great admiration” for Newton-John’s bravery facing breast cancer and wished “condolences to her loving family and friends.”

Julianne Hough, who channeled Sandy in Fox's "Grease: Live" in 2016, shared a touching tribute on Instagram.

"Like so many, Olivia has always been my hero," Hough wrote. "Discovering her magnetic energy as an artist and actress came first but it was her heart that truly captured mine. Forever an icon and legend!"

Oscar-winning actor Viola Davis thanked Newton-John for the eternal memories she created.

"Oh man!!! You were my childhood!! Your talent, poise, beauty!! Rest in glorious peace. God bless your family," Davis tweeted.

Fellow musician Dionne Warwick called Newton-John one of the most memorable artists she ever worked with.

"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," Warwick wrote.

Newton-John's friend Richard Marx shared photos of the two through the years on Twitter.

"My heart is broken," Marx wrote. "Rest now, sweet friend. You were as kind and loving a person as there's ever been. I'll miss you every day."

Marx's wife Daisy Fuentes also paid tribute to Newton-John, calling her a "childhood idol, a super talent."

Fuentes wrote on Twitter, alongside a selfie of the two, that Newton-John was "so brave, always elegant & one of the most beautiful souls I've ever met."

"Guardians of the Galaxy" director James Gunn wrote Newton-John was his "first real crush as a kid" on Twitter.

"Really sad to hear about the passing of Olivia Newton-John," Gunn said. "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."

"My So-Called Life" actor Wilson Cruz thanked Newton-John on Twitter for her positive impact on the LGBTQ community.

"I’ll never forget how lovingly and movingly #OliviaNewtonJohn spoke of her love and dedication for her #LGBTQ friends and people living with #AIDS at a screening of It’s My Party, the classic indie queer film. She was a true ally to us at one of our darkest moments," Cruz said.

Antonio Banderas took to Twitter to share photos of Newton-John and express his "deepest condolences to her family and loved ones."

“Motherland: Fort Salem” star Taylor Hickson wrote that she was “absolutely rocked” by the news.

"Thank you for inspiring my childhood alongside many other young girls,” she added. “May an icon rest beautifully xx”

"Bring It On" actress Gabrielle Union said her love for Newton-John started with "Grease," her favorite film.

"'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. #RIPOliviaNewtonJohn," Union said.

“Smallville” actor Michael Rosenbaum called the news of Newton-John’s death “crushing.”

“I absolutely loved this woman,” he wrote. “what a damn shame. so young. so talented.”

This article originally appeared on USA TODAY: Olivia Newton-John: John Travolta mourns singer, 'Grease' co-star