Christina Aguilera
Christina Aguilera performs onstage during Hollywood Stands Up To Cancer Event with contributors American Cancer Society and Bristol Myers Squibb hosted by Jim Toth and Reese Witherspoon and the Entertainment Industry Foundation on Tuesday, Jan. 28, 2014, in Culver City, California.
Christina Aguilera
Christina Aguilera performs onstage during 102.7 KIIS FM's 2014 Wango Tango at StubHub Center on May 10, 2014, in Los Angeles.
Christina Aguilera
Singer/songwriter Christina Aguilera attends Hollywood Stands Up To Cancer Event with contributors American Cancer Society and Bristol Myers Squibb hosted by Jim Toth and Reese Witherspoon and the Entertainment Industry Foundation on Tuesday, Jan. 28, 2014, in Culver City, California.
Christina Aguilera
Christina Aguilera arrives for the 2013 American Music Awards at the Nokia Theatre L.A. Live in downtown Los Angeles, Nov. 24, 2013.
Christina Aguilera
Christina Aguilera speaks onstage during the 40th Anniversary American Music Awards nominations press conference at the JW Marriott Los Angeles at L.A. LIVE on Oct. 9, 2012, in Los Angeles.
Christina Aguilera
Christina Aguilera performs during the "Michael Forever" concert in memory of the late Michael Jackson at The Millenium Stadium in Cardiff, Wales on Oct. 8, 2011.
Christina Aguilera
Christina Aguilera speaks onstage during the NBCUniversal's "The Voice" press junket and cocktail reception on Aug. 12, 2012, in Los Angeles.
Christina Aguilera
Coach Christina Aguilera speaks onstage during the "The Voice" panel during the NBCUniversal portion of the 2012 Winter TCA Tour at The Langham Huntington Hotel and Spa on Jan. 6, 2012, in Pasadena, Calif.
Christina Aguilera
Christina Aguilera performs onstage at the 2011 American Music Awards held at Nokia Theatre L.A. LIVE on Nov. 20, 2011, in Los Angeles.
Christina Aguilera
Singer Christina Aguilera performs during the Bridgestone Super Bowl XLV Pregame Show at Dallas Cowboys Stadium on Feb. 6, 2011, in Arlington, Texas. She made headlines for flubbing the lines while singing the national anthem at the game's start.
Christina Aguilera
Christina Aguilera attends the "Burlesque" photocall at Villamagna Hotel on Dec. 9, 2010 in Madrid, Spain.
Christina Aguilera
Christina Aguilera and Cher attend the "Burlesque" photocall at Villamagna Hotel on Dec. 9, 2010 in Madrid, Spain.
Christina Aguilera
Christina Aguilera and Kristen Bell attend the "Burlesque" premiere in Tokyo on Dec. 7, 2010.
Christina Aguilera
Christina Aguilera arrives at the premiere of "Burlesque" at the Grauman's Chinese Theater on Nov. 15, 2010, in Los Angeles.
Christina Aguilera
Christina Aguilera attends a press conference promoting her film "Burlesque" in Tokyo on Dec. 6, 2010.
Christina Aguilera
Christina Aguilera blows a kiss at the ceremony to unveil her Hollywood Walk of Fame star in Hollywood, Calif., on Nov. 15, 2010.
Christina Aguilera
Christina Aguilera performs onstage during the 2010 American Music Awards held at Nokia Theatre on Nov. 21, 2010, in Los Angeles.
PICTURES: AMA 2010: Red Carpet
SPECIAL SECTION: Awards Season 2010
Christina Aguilera
Christina Aguilera is seen during the taping of "On The Record" with Fuse in Beverly Hills, Calif., on June 4, 2010.
Christina Aguilera
Christina Aguilera arrives at the MTV Movie Awards in Universal City, Calif., June 6, 2010.
More from the MTV Movie Awards
Christina Aguilera
Christina Aguilera poses at her "Inspire" fragrance launch at Macy's on Sept. 2, 2008, in New York.
Christina Aguilera
Christina Aguilera poses on the press line at the opening gala celebration of the Broad Contemporary Art Museum at LACMA in Los Angeles on Feb. 9, 2008.
Christina Aguilera
Tony Bennett and Christina Aguilera perform the song "Steppin' Out" during the 59th Primetime Emmy Awards, Sept. 16, 2007, in Los Angeles.
Christina Aguilera
Britney Spears, Madonna and Christina Aguilera perform onstage during the 2003 MTV Video Music Awards at Radio City Music Hall in New York on Aug. 28, 2003.
Christina Aguilera
Christina Aguilera arrives at the Vanity Fair Oscar Party on Feb. 27, 2005, in West Hollywood, Calif.
Christina Aguilera
Christina Aguilera performs at the 14th Annual GLAAD Media Awards at the Kodak Theatre on April 26, 2003, in Los Angeles.
Christina Aguilera
Christina Aguilera arrives at the VH1 Big In 2002 Awards held at Grand Olympic Auditorium in Los Angeles, Dec. 4, 2002.