Why Céline Dion's impromptu duet backstage at the Grammys has everyone talking

Céline Dion not only was a surprise presenter at the Grammy Awards in Los Angeles on Sunday (Monday in Australia), but she also enjoyed a surprise performance backstage.

The iconic singer, 55, performed a duet with Sonyae Elise backstage at the event, with Elise sharing an incredible clip of the moment on her Instagram from the evening.

"Highlights of an ICONIC night🥂 So inspired & proud of my girls," she wrote in her post.

Watch the video above.

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Dion, who is known for hits including My Heart Will Go On and Because You Loved Me, was dressed elegantly in a cream gold-embellished coat as she showed off her impressive vocals.

"Love this!!! so good to see Céline – thanks for this!" one fan wrote underneath the clip.

Dion appeared on stage at the Grammys earlier this week, following her diagnosis with stiff person syndrome.

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The international superstar, 55, stepped onto the stage at the 2024 Grammy Awards to roaring cheers and a standing ovation in a surprise appearance at the end of the ceremony to 2024 Grammy Awards.

"When I say that I'm happy to be here, I really mean it. From my heart," the five-time Grammy winner said to rousing applause.

"Those who have been blessed enough to be here, the Grammy, the awards, must never take for granted the tremendous love and joy that music brings to our lives and to people all around the world," Dion continued in her speech.

"Now it gives me great joy to present a Grammy award that two legends, Diana Ross and Sting, presented to me 27 years ago," she concluded, before presenting the gong to Swift.

Swift won Album of the Year for Midnights, making history while doing so. She is the only artist in Grammy history who has won Album of the Year four times, with the last time being for Folklore in 2021.

Dion stepped back from performing in 2022 after almost four decades in the spotlight, revealing in the process she had been diagnosed with stiff person syndrome.

Stiff person syndrome is a rare and incurable neurological disorder that causes muscle stiffness and spasming.

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According to the National Institute of Neurological Disorders and Stroke, symptoms of the disorder can include "extreme muscle stiffness, rigidity and painful spasms in the trunk and limbs, severely impairing mobility.

In 2023, Dion cancelled the rest of her European tour, citing her ongoing health issues.

Dion's sister said she was "praying for a miracle" after the legendary singer revealed her battle with stiff person syndrome late last year.

"She's doing everything to recover," Claudette Dion, 74, told Hello!

Claudette says family find it hard to help Céline, 55, as "little" is known about the illness that causes spasms in the body "impossible to control".

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Céline Dion previously was forced to postpone some tour dates due to her battle with the condition, which she said was affecting her voice.

It doesn't let her "sing the way I'm used to," she previously said.

Céline made the announcement in a video clip shared to social media, assuring fans she is doing everything she can to keep her symptoms at bay.

"I'm working hard with my sports medicine therapist every day to build back my strength and my ability to perform again," she said. "But I have to admit it's been a struggle."