For Mariah Carey, it’s always work, work, work, work, work. But this time, the singer, 55, had a special guest. Rihanna made an appearance during the final stop of Carey’s Christmas Time tour ...

"Epic" Mariah Carey autographed Rihanna's breast at her final Christmas concert in New York City Tuesday night after battling the flu.

Rihanna gets Mariah Carey to sign her boob during the grand finale holiday tour: “My man made me do this!” Mariah Carey returned to the stage after canceling two prior performances due to the flu.