In footage shared online, the British star can be seen breaking down in tears as they embrace at the Colosseum at Caesars Palace, where Dion has held her residency for more than a decade.
After a brief conversation as they held each other, Adele returned to the floor and told the audience, “Give it up for Ms. Celine Dion.”
An emotional Dion could be seen wiping her eyes with a tissue before standing up and waving to the audience as Adele continued to sing her hit When We Were Young.
In another clip, Adele hails Dion as “one of my favorite people of all time” as she gestures to the singing superstar in the audience.
The Rolling In The Deep singer has been vocal about her love for Dion over the years, calling her “Queen Celine” after attending one of her performances in a 2018 Instagram post.
Next to a picture of herself wearing a Dion T-shirt, she added: ‘What a show, absolute highlight of my life, thank you so much for your attention to the crowd and crazy humour. Happy new year lady x”
Dion returned the love then, sharing a photo on social media of herself posing next to Adele, who was wearing the singer’s merchandise.
She wrote: “I couldn’t make all my shows but I was thrilled @Adele came to one of them…. I love her so much!! – Celine xx”.
Adele returned to the Colosseum this weekend to continue her residency after taking time off to play a series of shows in Munich in a purpose-built outdoor arena.
Weekends With Adele began at Caesars Palace in Las Vegas in November 2022 and is scheduled to end in November of this year.
Her run of sold-out concerts at the venue, which seats about 4,000 people, was a success, but it also took its toll.
In July, she announced that she would be taking a “big break” from music after her upcoming concerts.
Dion made a triumphant return to live singing in the summer to close the Paris Olympics opening ceremony amid her battle with Stiff Face Syndrome (SPS).
She spoke openly about SPS, revealing her diagnosis in December 2022 after canceling her 2021 Las Vegas residency due to health issues.
The condition is a rare autoimmune neurological disease that most commonly causes muscle stiffness and painful spasms, according to the Johns Hopkins Medicine website.
In March 2003, Dion began her first residency at The Colosseum, which performed 717 concerts until December 2007.
She returned to the venue for her second stint in March 2011 and played 424 shows before calling it quits in June 2019.