Mariah Carey looks back on performing with Olivia Newton-John: 'We sang our hearts out'

Mariah Carey honestly loves Olivia Newton-John — and always will.

In the wake of Newton-John's death Monday at 73, Carey paid a heartfelt tribute to the Grammy-winning singer and Grease star, noting that she was a lifelong fan of Newton-John's music and grew up listening to her hits.

"I first fell in love with Olivia's voice when I was a little girl and heard 'I Honestly Love You,'" Carey tweeted Monday evening. "Songs like 'Magic,' 'Suddenly' and 'Have You Never Been Mellow' showcased her beautiful airy tone and signature sound. And THEN there was GREASE. I was obsessed."

Carey went on to recall a beloved memory of sharing the stage with Newton-John: While Carey was on tour Down Under in 2002, Newton-John surprised the crowd by stopping by to sing one of her signature songs.

"I dressed up as Bad Sandy for Halloween in 5th grade and thought I was everything," Carey wrote. "Years later, THE Olivia Newton-John walked out onto my stage in Melbourne, Australia and we sang our hearts out together to 'Hopelessly Devoted To You.' This is a moment I will never ever forget."

As captured in the video below, Carey set the scene by revealing that she once won a talent competition singing "Hopelessly Devoted to You." Then, to the crowd's delight, she introduced her special guest: "Ladies and gentlemen, Olivia Newton-John!"

Carey concluded her Twitter tribute by sharing more pictures of her and Newton-John together. "I was also blessed to be in her presence on many other occasions and she was one of the kindest, most generous and lovely people I've ever met," she wrote. "She will be missed. She will be remembered. She will be loved. Olivia, I honestly love you."

Carey is just one of many celebrities who have paid their respects to Newton-John since her passing; others include Jane Lynch, Dione Warwick, Melissa Ethridge, Gabrielle Union, Geroge Takei, and Grease star John Travolta, who wrote on social media, "My dearest Olivia, you made all of our lives so much better. Your impact was incredible."

Related content:

• Olivia Newton-John, Grease star and Grammy-winning singer, dies at 73

• John Travolta posts tribute to late Grease costar, Olivia Newton-John

• Olivia Newton-John and John Travolta reprise their Grease characters for the first time ever