Top 20 Countdown Sneak: Andy Grammer Pranks Train On Tour, Wiz Khalifa Raps On Fall Out Boy’s “Uma Thurman Remix” + More On Last Lap

Ariana Grande makes her big screen debut, Eminem brings out all of Detroit’s superstars in his new video, the Black Keys cancel their European tour and more on Last Lap.

• Watch Andy Grammer recall the time he wore a dress to prank Train in front of a huge crowd on tour and catch the premiere of Train’s “Bulletproof Picasso” on Top 20 Countdown tomorrow at 9/8C on VH1.