The "Me!" singer passionately sang along to Mimi's greatest hits, reacting to Carey perfectly hitting the high notes, dancing along to her jams and even getting visibly emotional while singing along to "Hero." The camera could not stop panning over to Swift, who energetically showed how excited she was while watching the performance.
Naturally, Swifties took to social media to share their reactions.
After her performance, Carey accepted the prestigious Icon Award from presenter Jennifer Hudson, who was almost overcome with emotion as she handed the music legend the coveted trophy. Thanking her devoted fans, Carey expressed how they are "unlike any other entity I have ever known."
"And to anyone who's ever told me that a song I wrote helped save your life, I thank you, because you saved mine," she added as her eyes welled up with tears. "And I'll be eternally grateful for that. I love you so much."
All the while, Swift screamed "I love you" from the audience as Carey accepted the award.
That night, Swift and Panic! At the Disco's Brendon Urie opened the awards show, performing "ME!" live for the first time. The single dropped last Friday at midnight after weeks of buildup and teasing with cryptic Instagram posts and a mysterious countdown clock that whipped fans into a frenzy over her new music.