Britney Spears met Kevin Federline while he was working as a backup dancer for the pop princess. A whirlwind romance ensued.
The couple had two children together: Sean Preston Federline, born on September 14, 2005, and Jayden James Federline, who was born on September 12, 2006.
In July 2004, Spears became engaged to American dancer Kevin Federline, whom she had met three months before. The romance received intense attention from the media, since Federline had recently broken up with actress Shar Jackson, who was still pregnant with their second child at the time. The stages of their relationship were chronicled in Spears's first reality show Britney & Kevin: Chaotic. They held a wedding ceremony on September 18, 2004, but were not legally married until three weeks later on October 6 due to a delay finalizing the couple's prenuptial agreement. Shortly after, she released her first fragrance with Elizabeth Arden, Curious, which broke the company's first-week gross for a perfume. In October 2004, Spears took a career break to start a family. Greatest Hits: My Prerogative, her first greatest hits compilation album, was released in November 2004. Spears's cover version of Bobby Brown's "My Prerogative" was released as the lead single from the album, reaching the top of the charts in Finland, Ireland, Italy and Norway. The second single, "Do Somethin'", was a top ten hit in Australia, the United Kingdom and other countries of mainland Europe.The greatest hits album sold over 5 million copies worldwide. In September 2005, Spears gave birth to her first child, Sean Preston Federline.
In February 2006, pictures surfaced of Spears driving with her son Sean, on her lap instead of in a car seat. Child advocates were horrified by the photos of her holding the wheel with one hand and Sean with the other. Spears claimed that the situation happened because of a frightening encounter with paparazzi, and that it was a mistake on her part. The following month, she guest-starred on the Will & Grace episode "Buy, Buy Baby" as closeted lesbian Amber Louise. She announced she no longer studied Kabbalah in June 2006, explaining, "my baby is my religion." Two months later, Spears posed nude for the cover of Harper's Bazaar. The picture was heavily compared to Demi Moore's August 1991 Vanity Fair cover. In September 2006, she gave birth to her second child, Jayden James Federline. In November 2006, Spears filed for divorce from Federline, citing irreconcilable differences. Their divorce was finalized in July 2007, when the couple reached a global settlement and agreed to share joint custody of their children.
In October 2007, Spears lost physical custody of her children to Federline. The reasons of the court ruling were not revealed to the public.