Ludacris 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)
Austin Mahone 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)
Gerard Pique, left, and Shakira 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 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)
Kendall Jenner, left, and Kylie Jenner 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)
Ben McKee, from left, Dan Reynolds, Wayne Sermon and Daniel Platzman, of the musical group Imagine Dragons, 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)
Kendall Jenner 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)
Kylie Jenner 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)
Gerard Pique, left, and Shakira 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)
Lance Bass 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)
Jordin Sparks 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)
Jackie Jackson 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)
Phillip Phillips 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)
Josh Groban 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)