At an opening party for the Croatian Open tournament in Umag, Alexandr Dolgopolov of the Ukraine appeared on stage to perform, with the help of a hook-singing gentleman, "Gangsta's Paradise" by Coolio. The ATP World Tour put up the video here.
But that's not all. Gael Monfils then joined "The Dog" on stage for a rendition of Eminem's "The Real Slim Shady"—behold. (Caution: very explicit language.)
There's precedent for this. In 2011, Dolgopolov teamed up with a female singer for a live version of Rihanna and Eminem's hit, "Love the Way You Lie." Roll footage: