25) DEMI LOVATO

LOS ANGELES, CA - SEPTEMBER 06: Demi Lovato performs outside the 2012 MTV Video Music Awards at Staples Center on September 6, 2012 in Los Angeles, California. (Photo by Christopher Polk/Getty Images)

24) NE-YO

Ne-Yo poses on arrival for the GQ Men of the Year Party at Chateau Marmont on Sunset Blvd., in Hollywood, California, on November 13, 2012. AFP PHOTO / Frederic J. BROWN (Photo credit should read FREDERIC J. BROWN/AFP/Getty Images)

23) BRUNO MARS

LAS VEGAS, NV - FEBRUARY 16: Singer Bruno Mars performs onstage at Club SI Swimsuit hosted by the Pure Nightclub at Caesars Palace at the Pure Nightclub at Caesars Palace on February 16, 2012 in Las Vegas, Nevada. (Photo by Michael Loccisano/Getty Images for Sports Illustrated)

22) ADELE

British singer-songwriter Adele poses on the red carpet arriving at the BRIT Awards 2012 in London on February 21, 2012. AFP PHOTO / BEN STANSALL (Photo credit should read BEN STANSALL/AFP/Getty Images)

21) HAVANA BROWN

MELBOURNE, AUSTRALIA - OCTOBER 16: DJ Havana Brown performs in support of The Pussycat Dolls at the Ford Live! Event in aid of The National Breast Cancer Foundation at the Queensbridge Hotel on October 16, 2008 in Melbourne, Australia. (Photo by Kristian Dowling/Getty Images)

20) fun.

LOS ANGELES, CA - SEPTEMBER 06: Musicians Andrew Dost, Jack Antonoff and Nate Ruess of the band Fun arrives at the 2012 MTV Video Music Awards at Staples Center on September 6, 2012 in Los Angeles, California. (Photo by Christopher Polk/Getty Images)

19) CHRIS BROWN

LOS ANGELES, CA - NOVEMBER 18: Singer Chris Brown attends the 40th American Music Awards held at Nokia Theatre L.A. Live on November 18, 2012 in Los Angeles, California. (Photo by Jason Merritt/Getty Images)

18) TAYLOR SWIFT

LOS ANGELES, CA - DECEMBER 01: Musician Taylor Swift performs onstage during KIIS FM's 2012 Jingle Ball at Nokia Theatre L.A. Live on December 1, 2012 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for Clear Channel)

17) GYM CLASS HEROES

NEW YORK, NY - SEPTEMBER 16: Disashi Lumumba-Kasongo, Travie McCoy, Matt McGinley, and Eric Roberts of Gym Class Heroes attend the Pop-Tarts Pops Up In NYC With A Free Concert For Teens Starring Gym Class Heroes And Allstar Weekend at Irving Plaza on September 16, 2012 in New York City. (Photo by Jeff Schear/Getty Images for Kelloggs Pop Tarts)

16) USHER

LAS VEGAS, NV - SEPTEMBER 21: Recording artist Usher performs onstage during the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 21, 2012 in Las Vegas, Nevada. (Photo by Christopher Polk/Getty Images for Clear Channel)

15) PITBULL

LAS VEGAS, NV - MARCH 30: Armando 'Pitbull' Perez, winner of the BMI President's Award, performs during the 19th Annual BMI Latin Music Awards at the Encore Las Vegas on March 30, 2012 in Las Vegas, Nevada. (Photo by David Becker/Getty Images)

14) DRAKE

Recording artist Drake arrives at the 2010 MTV Video Music Awards at the Nokia Theater in Los Angeles on Sepetember 12, 2010. AFP PHOTO / ROBYN BECK (Photo credit should read ROBYN BECK/AFP/Getty Images)

13) KATY PERRY

HOLLYWOOD, CA - JUNE 26: Singer Katy Perry arrives at the premiere of "Katy Perry: Part Of Me" held at Grauman's Chinese Theatre on June 26, 2012 in Hollywood, California. The premiere also included a special live performance by Katy for the first-ever Pepsi/Billboard Summer Beats series. "Katy Perry: Part Of Me" will be released by Paramount's Insurge Pictures on July 5, 2012. (Photo by Jason Merritt/Getty Images)

12) ELLIE GOULDING

LOS ANGELES, CA - DECEMBER 01: Recording artist Ellie Goulding performs onstage during KIIS FM's 2012 Jingle Ball at Nokia Theatre L.A. Live on December 1, 2012 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for Clear Channel)

11) CARLY RAE JEPSEN

LOS ANGELES, CA - OCTOBER 02: Singer Carly Rae Jepsen performs at The Staples Center on October 2, 2012 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)

10) JUSTIN BIEBER

NEW YORK, NY - NOVEMBER 07: Justin Bieber attends the 2012 Victoria's Secret Fashion Show at the Lexington Avenue Armory on November 7, 2012 in New York City. (Photo by Stephen Lovekin/Getty Images)

9) LMFAO

LOS ANGELES, CA - JUNE 05: Singers Redfoo (L) and Sky Blu of LMFAO perform at the Staples Center on June 5, 2012 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)

8) THE WANTED

NEW YORK, NY - NOVEMBER 22: The Wanted attend the 86th Annual Macy's Thanksgiving Day Parade on November 22, 2012 in New York City. (Photo by Laura Cavanaugh/Getty Images)

7) DAVID GUETTA

INDIO, CA - APRIL 14: DJ David Guetta performs onstage at the 2012 Coachella Valley Music & Arts Festival held at The Empire Polo Field on April 14, 2012 in Indio, California. (Photo by Mark Davis/Getty Images for Coachella)

6) MAROON 5

US music group Maroon 5 members (L-R) Matt Flynn, PJ Morton, Adam Levine, Mickey Madden and James Valentine pose for a picture during a press conference in Mexico City, on August 16, 2012. Maroon 5 is in Mexico for a series of concerts. AFP PHOTO/RONALDO SCHEMIDT (Photo credit should read Ronaldo Schemidt/AFP/GettyImages)

5) ONE DIRECTION

DUESSELDORF, GERMANY - NOVEMBER 22: Harry Styles, Zayn Malik, Louis Thompson, Liam Payne and Niall Horan attend the 'BAMBI Awards 2012' at the Stadthalle Duesseldorf on November 22, 2012 in Duesseldorf, Germany. (Photo by Andreas Rentz/Getty Images)

4) CALVIN HARRIS

LAS VEGAS, NV - SEPTEMBER 22: DJ Calvin Harris performs onstage during the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 22, 2012 in Las Vegas, Nevada. (Photo by Isaac Brekken/Getty Images for Clear Channel)

3) NICKI MINAJ

SYDNEY, AUSTRALIA - NOVEMBER 29: Nicki Minaj poses during an event to celebrate the launch of her new perfume at Myer Sydney City on November 29, 2012 in Sydney, Australia. (Photo by Mark Metcalfe/Getty Images)

2) FLO RIDA

SANTA MONICA, CA - AUGUST 19: Flo Rida performs onstage during the 2012 Do Something Awards at Barker Hangar on August 19, 2012 in Santa Monica, California. (Photo by Kevin Winter/Getty Images for VH1)

1) RIHANNA

BEVERLY HILLS, CA - APRIL 18: Singer Rihanna performs onstage at the 15th Annual "An Unforgettable Evening" Benefiting EIF's Women's Cancer Research Fund held at The Beverly Hilton Hotel on April 18, 2012 in Beverly Hills, California. (Photo by John Shearer/Getty Images for Entertainment Industry Foundation)