Ellen Degeneres dared viewers to send in footage of themselves committing a prank, Ellen dubbed "Dance Dare." (It's basically dancing around someone without them catching you.)
Obvi, The Lorax co-stars Taylor Swift and Zac Efron got wind of the new prank and wanted in on the fun. Because at the premiere of flick, the co-stars Dance Dared all up and around some of Hollywood's hottest celebs! LOLZ!
Watch the video (above) to see which star was the only one awesome enough to catch the pranksters in the act!