The "Hero" star is currently in the middle of her Mariah Carey #1 to Infinity residency at The Colosseum at Caesars Palace, and when she performed her hit "Touch My Body", she invited the R&B star to join her on stage.
Legend happily jumped onto Carey's prop bed and one of the male dancers blindfolded him from behind as the diva stood next to him. She then teased him by rubbing a large pink feather on the back of his neck, much to his amusement.
She also shared a clip of Legend's supermodel wife Chrissy Teigen in the audience, as she screamed and cheered her husband on while Mariah serenaded her man.
New mother Chrissy shared the same video on her Instagram page, and gushed over the moment, writing, "Mariah pulled @johnlegend on stage at her Vegas show and as a lamb (fan), I have never been so happy.