Iggy Azalea (L) and Ariana Grande perform onstage during the 2014 Billboard Music Awards held at MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Michael Tran/FilmMagic)

A festival goer uses a hula hoop, as revelers gather ahead of this weekends Glastonbury Festival of Music and Performing Arts on Worthy Farm in Somerset, southwest England, on June 25, 2014. US metal giants Metallica will play this year's coveted Saturday night headline spot at Britain's Glastonbury festival, organisers announced Thursday. It will be the “Master of Puppets” four-piece's first appearance at the legendary festival, held in south west England, following on from The Rolling Stones' Worthy Farm debut last year. (Photo by Leon Neal/AFP Photo)

Miss California Crystal Lee performs during the Miss America 2014 pageant, Sunday, September 15, 2013, in Atlantic City, N.J. (Photo by Mel Evans/AP Photo)

Taylor Swift performs “All Too Well” at the 56th annual Grammy Awards at Staples Center. (Photo by Matt Sayles/Invision)

Actress Zendaya arrives at the 27th Annual Kids' Choice Awards in Los Angeles, California March 29, 2014. (Photo by Danny Moloshok/Reuters)

Runners cross the Verrazano-Narrows Bridge shortly after the start of the New York City Marathon in New York, November 2, 2014. (Photo by Lucas Jackson/Reuters)

Bex Hetherington exhibits a T-shirt at the Edinburgh College of Art degree show on June 8, 2011 in Edinburgh, Scotland. Students work will be exhibited across the campus buildings turning Edinburgh College of Art into the city's biggest gallery space. The work ranges from conceptual to commercial with inspirational influences as diverse and wide ranging as fashion photography, volcanoes, the crazy lady who put a cat in a bin, fairytales, the star system and serial killers. (Photo by Jeff J Mitchell/Getty Images)

Dilwyn Green, from North Wales, holds his 7 month old Gold Silkie Bantam which won a 1st prize in its breed at the Poultry Club's 2011 National Show on November 19, 2011 in Stoneleigh, England. (Photo by Oli Scarff/Getty Images)