NEW YORK, NY - DECEMBER 17: (EXCLUSIVE COVERAGE) John Mayer and Katy Perry perform at Barclays Center of Brooklyn on December 17, 2013 in New York City. (Photo by Zachary Mazur/WireImage)
NEW YORK, NY - DECEMBER 17: (EXCLUSIVE COVERAGE) John Mayer and Katy Perry perform at Barclays Center of Brooklyn on December 17, 2013 in New York City. (Photo by Zachary Mazur/WireImage)