Difference between taking pictures with Britney Spears and Rihanna:
Adam Rifkin stashed this in Selfie
But so help her, if you are Michael Cera and you touch her butt you are getting knocked out.
Michael Cera asked if he could actually smack Rihanna's butt for realism in the movie This is the End, and she said only if she could slap him for real. They both agreed.