LAS VEGAS, NV - MAY 15: Britney Spears and Iggy Azalea perform at the 2015 Billboard Music Awards on May 15, 2015 in Las Vegas, Nevada. The Billboard Awards will air on May 17, 2015. (Photo by Denise Truscello/Getty Images for Britney Spears)
LAS VEGAS, NV - MAY 15: Britney Spears and Iggy Azalea perform at the 2015 Billboard Music Awards on May 15, 2015 in Las Vegas, Nevada. The Billboard Awards will air on May 17, 2015. (Photo by Denise Truscello/Getty Images for Britney Spears)