Carrie Underwood & Miranda Lambert attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Jennifer Lopez attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Kendall & Kylie Jenner attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Kylie Jenner attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Kendall Jenner attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Carrie Underwood attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

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Shakira backstage at the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Nicki Minaj attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Nicki Minaj attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Ariana Grande attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Lucy Hale attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Lorde attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Andi Dorfman attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Chrissy Teigen attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Kelly Rowland attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Iggy Azalea attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Miranda Lambert attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Jordan Sparks attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Ke$ha attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Sarah Hyland attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Sarah Hyland attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Iggy Azalea attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Rocsi Diaz attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Danica McKellar attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Amber Rose attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Shania Twain attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Keltie Knight attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Liz Hernandez attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Renee Bargh attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Lauren Elizabeth attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Jennifer Lopez attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Aubrey Peeples attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Carrie Underwood attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Anita Patrickson attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Charli XCX attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Lucy Hale attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Natasha Bedingfield attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)

Nicki Minaj, in Alexander McQueen, attends the 2014 Billboard Music Awards at the MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Frazer Harrison/Getty Images)