Luke Bryan poses in the press room with the award for top country artist at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Eric Jamison/Invision/AP)
Robin Thicke performs on stage at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Chris Pizzello/Invision/AP)
Ricky Martin arrives at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by John Shearer/Invision/AP)
Chrissy Teigen, left, and John Legend arrive at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by John Shearer/Invision/AP)
Casper Smart, left, and Jennifer Lopez arrive at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by John Shearer/Invision/AP)
Shania Twain, left, presents the award for top rock album to Dan Reynolds, of the musical group Imagine Dragons, at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Chris Pizzello/Invision/AP)
Shakira performs at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Chris Pizzello/Invision/AP)
Ricky Martin performs on stage at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Chris Pizzello/Invision/AP)
Charli XCX, left, and Iggy Azalea perform on stage at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Chris Pizzello/Invision/AP)
Lorde performs on stage at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Chris Pizzello/Invision/AP)
Miranda Lambert, left, and Carrie Underwood perform on stage at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Chris Pizzello/Invision/AP)
Wayne Sermon, left, and Dan Reynolds, of the musical group Imagine Dragons, perform at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Chris Pizzello/Invision/AP)
Carrie Underwood, left, and Miranda Lambert arrive at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by John Shearer/Invision/AP)
Jennifer Lopez accepts the icon award at the Billboard Music Awards at the MGM Grand Garden Arena on Sunday, May 18, 2014, in Las Vegas. (Photo by Chris Pizzello/Invision/AP)