Selena Gomez performs at the MTV Movie Awards. (Photo by Jordan Strauss/Invision for MTV)

Co-hosts Kat Dennings (L) and Beth Behrs onstage at The 40th Annual People's Choice Awards show at Nokia Theatre LA Live on January 8, 2014 in Los Angeles, California. (Photo by Allen Berezovsky/WireImage)

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)

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)

Singer Ariana Grande performs during the 2014 MTV Europe Music Awards at the SSE Hydro Arena in Glasgow, on November 9, 2014. (Photo by Toby Melville/Reuters)

Singer Rihanna in the audience at the 54th Annual GRAMMY Awards held at Staples Center on February 12, 2012 in Los Angeles, California. (Photo by Larry Busacca/Getty Images For The Recording Academy)

Taylor Swift performs at the Billboard Music Awards. (Photo by Chris Pizzello/Invision)