Spears initially supported the policies of President Bush in a CNN interview in 2003 with conservative political pundit Tucker Carlson. However, her support was not due to politics; instead more to show patriotism. Carlson praised Spears for her support of the president, who was unpopular at that time among Hollywood entertainers.
Spears released her fourth studio album In the Zone in November 2003, jettisoning the Max Martin-produced synthpop of her earlier releases. The album took in lesser-known producers such as RedZone and big names including Moby and R. Kelly. Spears co-wrote eight of the album's thirteen songs and co-produced several pieces of her material for the first time. In the Zone reached number one in the U.S. charts during its debut week, selling over 609,000 copies. This made Spears the first female in the Nielsen SoundScan era to have her first four studio albums to debut at number one. The album had a mild reception from critics. Stylus Magazine gave the album a D and even blamed Spears's career choices by stating, "Ultimately, In the Zone suffers greatly from Britney's uneasy transition from teen tart to sexually powerful woman. Had Britney been in charge of her career direction instead of mercilessly prostituted by her management, she might have been able to produce something with some semblance of musical vision." The Guardian praised the album's melodies and her effort, giving it 4 out of 5 stars and writing, "Unlike previous Britney albums, In the Zone has no filler and no shoddy cover versions, just 57 varieties of blue-chip hit-factory pop. There is southern hip-hop, deep house, Neptunes-style R&B, the ubiquitous Diwali beat and, most importantly, oodles of Madonna."
The album spawned the hit single "Toxic", winning Spears her first ever Grammy in the category of Best Dance Recording.
2004-2005: Marriages, first child and compilation albums
Spears married childhood friend Jason Allen Alexander on January 3, 2004, at The Little White Wedding Chapel in Las Vegas. The marriage lasted 55 hours, ending with an annulment stating that Spears "lacked understanding of her actions to the extent that she was incapable of agreeing to marriage because before entering into the marriage the Plaintiff and Defendant did not know each others' likes and dislikes, each others' desires to have or not have children, and each other's desires as to State of residency."
Months after her Las Vegas marriage, Spears embarked on The Onyx Hotel Tour, which was canceled in June, after Spears injured her knee during the filming of the video for the single "Outrageous". The tour's choreography generated much controversy and criticism, with the presence of young children in the audience. She then became involved in the Kabbalah Centre in September 2004 through her friendship with Madonna. However, she publicly left the religion in 2006, stating on her website, "I no longer study Kabbalah, my baby is my religion."
In July 2004, Spears announced her engagement to Kevin Federline, three months after they met. Federline had recently been in a relationship with actress Shar Jackson, who was eight months pregnant with their second child. These initial stages were chronicled in Spears's first reality show Britney & Kevin: Chaotic, which aired on UPN in May and June 2005. On the night of September 18, Spears married Federline in a surprise, non-denominational ceremony at a residence in Studio City, California, filing legal papers on October 6. After the marriage, Spears announced via her website that she would be taking another career break to start a family. She gave birth to her first child, Sean Preston Federline, nearly one year later, on September 14, 2005 in Santa Monica, California by a scheduled caesarean section.
November 2004 saw the release of her first greatest hits collection, Greatest Hits: My Prerogative, which features all of Spears's singles with the exception of "From The Bottom Of My Broken Heart". It also featured three previously unreleased songs, them being a cover version of American R&B singer Bobby Brown's 1988 hit "My Prerogative", "Do Somethin'", produced by Bloodshy and Avant, whom she had worked with on In The Zone, and "I've Just Begun (Having My Fun)", which was a song recorded for Spears's fourth album, In The Zone, but did not make the final cut. By the end of that year, Spears had become one of the best-selling artists in the world.
In November 2005, Spears released her first remix album, B In The Mix: The Remixes. The album ranged from "...Baby One More Time" to "Toxic". Her single "Someday (I Will Understand)" was also remixed. Another single, "And Then We Kiss", was only released in Asia, where it charted in many countries. The song peaked at number 15 on Billboard's Hot Dance Airplay chart, despite it not being officially released in the U.S.
2006-2007: Personal struggles, second child, divorce, and Blackout
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'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