Britney Spears is one of the most successful pop artists of all time. In her early days, Spears appeared on Disney's The New Mickey Mouse Club alongside fellow future pop stars Christina Aguilera and Justin Timberlake. In 1999, Spears released her debut album ...Baby One More Time. The record instantly propelled her to stardom and topped charts around the globe, selling more than 25 million copies since its release. The album's titular single, which raised concerns with Spears appearing as a provocatively dressed schoolgirl in the video clip, was named number 25 on MTV's 100 Greatest Pop Songs of all time and sold nine million copies on release. Spears followed this release with the equally successful album Oops!... I Did It Again (2000), which debuted at number one in the US, broke SoundScan's record for highest album sales for a solo artist in its debut week and has sold more than 20 million copies to date. Her fourth album, In The Zone, produced the hit, Grammy award-winning single 'Toxic'. In 2004, Spears married dancer Kevin Federline. Their heavily publicised relationship put a major question mark above Britney's musical future and produced their sons Sean Preston, born in 2005, and Jayden James, in 2006. The relationship between Spears and Federline soon soured, ending in divorce and an ongoing custody battle - which ended in 2007 with the court giving Federline primary custody of the children. Despite her troubles, Spears went on to release her fifth studio album, Blackout, in 2007, to mild reviews.