...Baby One More Time Tour (01 of17)
Open Image ModalTeen pop sensation, Britney Spears performing at Universal Ampitheater for her 'Baby One More Time' tour in Universal City, CA. July 31, 1999. (credit:Brenda Chase/Online USA, Inc.)
Ooops! I Did It Again Tour(02 of17)
Open Image ModalBritney Spears performs onstage during her concert on the 'Ooops! I Did It Again' Tour in Paris,France on the 7th of May 2000. (credit:Dave Hogan/Getty Images)
Oops I Did It Again Tour(03 of17)
Open Image Modal American pop star Britney Spears performs on stage during her 'Oops I Did It Again' Tour on July 5, 2000 in London. (credit:Dave Hogan/Getty Images)
Onyx Hotel Tour(04 of17)
Open Image ModalSinger Britney Spears performs onstage during Showtime's live broadcast of Britney's Onyx Hotel tour show at the American Airlines Arena March 28, 2004 in Miami, Florida. (credit:Getty Images Frank Micelotta/Getty Images)
Onyx Hotel Tour(05 of17)
Open Image ModalMIAMI - MARCH 28: (U.S. TABS AND STAR MAGAZINE OUT) Singer Britney Spears performs onstage during Showtime's live broadcast of Britney's Onyx Hotel tour show at the American Airlines Arena March 28, 2004 in Miami, Florida. (credit:Frank Micelotta/Getty Images)
Onyx Hotel Tour(06 of17)
Open Image ModalSinger Britney Spears performs onstage during Showtime's live broadcast of Britney's Onyx Hotel tour show at the American Airlines Arena March 28, 2004 in Miami, Florida. (credit:Frank Micelotta/Getty Images)
Onyx Hotel Tour(07 of17)
Open Image ModalSinger Britney Spears performs onstage during Showtime's live broadcast of Britney's Onyx Hotel tour show at the American Airlines Arena March 28, 2004 in Miami, Florida. (credit:Frank Micelotta/Getty Images)
The Circus Starring Britney Spears Tour(08 of17)
Open Image ModalSinger Britney Spears performs onstage during the opening night of 'The Circus Starring Britney Spears' tour at the New Orleans Arena on March 3, 2009 in New Orleans, Louisiana. (credit:Kevin Mazur/Getty Images for Jive Records)
The Circus Starring Britney Spears tour (09 of17)
Open Image ModalSinger Britney Spears performs onstage during the opening night of 'The Circus Starring Britney Spears' tour at the New Orleans Arena on March 3, 2009 in New Orleans, Louisiana. (credit:Getty Images)
The Circus Starring Britney Spears Tour(10 of17)
Open Image ModalSinger Britney Spears performs onstage during the opening night of 'The Circus Starring Britney Spears' tour at the New Orleans Arena on March 3, 2009 in New Orleans, Louisiana. (credit:Getty Images)
The Circus Starring Britney Spears Tour(11 of17)
Open Image ModalBritney Spears kicks off her Circus Tour at the New Orleans Arena, March 3, 2009. (credit:Andrew Theodorakis/NY Daily News Archive via Getty Images)
Femme Fatale Tour(12 of17)
Open Image ModalFILE - In this Sept. 24, 2011 file photo, singer Britney Spears performs on a stage during a concert in Moscow, Russia, during her European Femme Fatale tour, Sept. 24, 2011 (credit:AP)
Femme Fatale Tour(13 of17)
Open Image ModalIn this Sept. 27, 2011 file photo, singer Britney Spears performs on a stage during a concert in Kiev, Ukraine, during her European Femme Fatale Tour. (credit:AP Photo/Leonid Naidiouk,)
Femme Fatale Tour(14 of17)
Open Image ModalBritney Spears performs on a stage during a concert in Kiev, Ukraine, Tuesday late, Sept. 27, 2011. Britney Spears performs in Moscow, St.Petersburg and Kiev as part of her European Femme Fatale Tour. (credit:AP Photo/Leonid Naidiouk)
Femme Fatale Tour(15 of17)
Open Image Modal (credit:Alamy)
Femme Fatale Tour(16 of17)
Open Image ModalBritney Spears performs on stage during a concert in Kiev, Ukraine, Tuesday, Sept. 27, 2011. Spears performs in Moscow, St. Petersburg and Kiev as part of her European Femme Fatale tour. (AP Photo/Yaroslav Debelyi) (credit:AP)
Femme Fatale Tour(17 of17)
Open Image ModalBritney Spears, center, performs on a stage during a concert in Moscow, Russia, Saturday, Sept. 24, 2011. Britney Spears performs in Moscow, St.Petersburg and Kiev as part of her European Femme Fatale Tour. (AP Photo) (credit:AP)