2006–2007

In 2006, Spears guest-starred on the Will & Grace episode "Buy, Buy Baby" as a closeted lesbian. Spears announced her second pregnancy in May 2006 during an appearance on The Late Show with David Letterman. She also appeared on Dateline the next month to discuss tabloid rumors about an impending divorce, and motherhood. She addressed an incident which occurred in February when photos revealed her driving with her son unrestrained in her lap, explaining, "I see a bunch of photographers and I’m scared and I want to get out of the situation... They’re coming up on the sides of the car which is a scary situation for me… so I get my baby out of the car and I go home." The month following the televised interview, Spears posed nude for the August 2006 cover of Harper's Bazaar. Just two days before Sean's first birthday, Spears gave birth to her second son, Jayden James Federline on September 12 in Los Angeles. Spears filed for divorce from Federline on November 7, 2006, citing irreconcilable differences and asking for both physical and legal custody of their two children, with visitation rights for Federline. The following day, Federline filed a response to Spears's divorce petition, seeking physical and legal custody of their children. American attorney Laura Wasser was hired to represent Spears in the case. According to a representative for Federline's lawyer, the divorce filing "caught Kevin totally by surprise". The couple reached a global settlement agreement in March 2007 and their divorce was finalized in July. Spears's aunt Sandra Bridges Covington, with whom she had been very close, died of ovarian cancer on January 21, 2007. Spears then stayed in an off-shore drug rehabilitation facility in Antigua for less than 24 hours on February 16. The following night at a hair salon in Tarzana, California she shaved her head with electric clippers. A few days later, she admitted herself to another treatment facility in Malibu, California. While leaving the facility briefly, she quickly returned on February 22. The previous day, Kevin Federline had requested an emergency hearing regarding the custody of their children but then his attorney announced that Federline asked to cancel the court appearance. No further explanation was given.

Throughout 2007, Spears's behavior received heightened media attention, including attacking a paparazzi vehicle with an umbrella. Spears left the rehabilitation center on March 20 according to her manager, who said she was released after "successfully completing their program." As the legal battle over the custody of their children continued, many members of her entourage have been summoned to testify about her parenting skills. In March 2007, Leonard Pitts, Jr. wrote that in the aftermath of Spears's personal struggles that have become widely publicized, Spears had been reduced to an abstract idea as opposed to being regarded as a real person. "The abstraction is not surprising: Whatever media touch, they objectify... What must it be like to have your marriage and divorce, your relationship with your parents and kids... dissected by millions of strangers who think they know you?" Pitts further commented that fame and fortune do not qualify the media scrutiny Spears has faced, but observed that fact has been overlooked by "our rush to a day of 'reality' television" and "tabloid journalism". Though " There is no reverence, no privacy, [and] nothing held back as sacred", Pitts argues "Britney Jean Spears is not an idea."

In May 2007, she produced a mini-tour for the House of Blues just after she left a rehabilitation facility under the name The M+M's; with six shows altogether, she sang live during some lines of her songs. She recorded her next album with producers such as Sean Garrett, J. R. Rotem and Nate "Danja" Hills throughout 2006 and 2007.

In September 2007, the official findings in Spears's custody battle were announced by the court. She was ordered to undergo random drug and alcohol testing and to attend parenting counseling. Spears and Federline continued to share joint custody of their two children on a conditional basis. A few days later, she was officially charged with misdemeanor hit-and-run and driving without a license. If convicted, she could have faced a year in jail. Spears lost physical custody of her children to Federline on October 1, with the court ruling that Federline will keep full custody of the children. The charges for her alleged hit-and-run that occurred in August 2007 were officially laid, she was booked for the charges by the Los Angeles Police Department on October 15 but was not arrested.

The release of Spears's fifth album, Blackout, was rescheduled to October 30, 2007 rather than November 13, 2007 due to online leaks. Blackout debuted at number two on the UK Albums Chart and the U.S. Billboard 200., making Spears the only female music artist to have her first five albums go to number one and two. It was fairly well received by critics. As of June 2008, there have been 3.1 million digital downloads of the songs and remixes from the album in the United States. Rolling Stone gave the album 3.5 out of 5 stars. Allmusic also rated the album 3.5 out of 5 stars, calling Blackout "coherent and entertaining" and stating that "it holds together better than any of her other records". Blackout's lead single, "Gimme More" leaked on the internet on August 30. The song, which was Spears's first produced by Danja, peaked at number three on Billboard Hot 100 on October 3, making it, at the time, her most successful single in the U.S. since her debut, "...Baby One More Time".

Spears's highly anticipated performance of "Gimme More" at the 2007 MTV Video Music Awards attracted worldwide attention which exceeded expectations. It became perhaps the most talked-about televised song and dance routine since her friend Michael Jackson's appearance a quarter century earlier on the Motown 25: Yesterday, Today, Forever special. Her singing, her dancing and even her wardrobe were all commented on extensively. The BBC stated that "her performance would go down in the history books as being one of the worst to grace the MTV Awards." The single rocketed to worldwide success.[not in citation given] The second single, "Piece of Me", peaked at No. 2 in the UK Singles Chart.

In December 2007, Spears began a relationship with Adnan Ghalib. Ghalib had been working as a paparazzi, taking photographs of Spears outside her house. Of his relationship with Spears, Ghalib stated, "I think she's a great person."