As executive producers, Larry Rudolph and Teresa LaBarbera Whites enlisted Spears' previous collaborators such as Max Martin, Bloodshy & Avant, Guy Sigsworth and Danja, as well as new ones, including Dr. Luke, Benny Blanco and Claude Kelly.

Throughout 2007, Spears' professional endeavors were tremendously overshadowed by her personal struggles, including the aftermath of her vigorous partying and suffering from a nervous breakdown, during which she shaved her head to intense media scrutiny.

The following day, Spears's visitation rights were suspended at an emergency court hearing, and Federline was given sole physical and legal custody of their sons.

The court placed her under a conservatorship led by her father Jamie Spears and attorney Andrew Wallet, giving them complete control of her assets.

[2] Alongside the announcement of Circus came the additional confirmation of the involvement of producers Sean Garrett, Guy Sigsworth, Danja and Bloodshy & Avant.

[19] During its development, Garrett and vocal producer Jim Beanz complimented Spears's work ethic after her much-publicized personal struggles the previous year.

The Outsyders, an Atlanta-based production team, produced the lead single "Womanizer",[26] while Fernando Garibay worked on "Amnesia" and "Quicksand", neither of which made the standard edition track listing.

[29] Lil Jon,[30] Rodney Jerkins,[31] Sean Garrett,[32] and Taio Cruz[33] announced they were working with Spears, though their songs weren't included on the final track listing.

Circus opens with its lead single "Womanizer", which features synth sirens with a repetitive chorus, and lyrically discusses a cheating man; it was described by Spears as a "girl anthem".

"If U Seek Amy" integrates "glam-rave" elements with traditional pop styles;[42] it gained controversy for its double entendre, where the title sounds phonetically like "F-U-C-K me".

It has been compared to musical themes from the 1980s and 1990s, and has been noted as a "pulsating ballad", with the song also drawing comparisons to the "shimmering waterfall mood first popularized by Janet Jackson".

[37][44][45] "Blur", which features Spears singing in a lower register, sees the inclusion of urban influences, and lyrically recalls the morning after a party: "Can't remember what I did last night/I gotta get my head right, where the hell am I?

[34] "Mannequin" is a trip hop-influenced dance-pop track; while being noted for its "risky" and "futuristic" nature, it has also been suggested that Spears' vocals sound "lifeless".

[49] "Lace and Leather" is an electro-funk track which gained comparisons to "Control era Janet Jackson", Prince, and Vanity 6's works from the 1980s, and featured a then-unknown Kesha as a backing vocalist.

[37][34] Circus closes with its bonus track "Radar", an electropop and Eurodisco song featuring distorted synthesizers emulating sonar pulses, which received comparisons to those of Soft Cell's "Tainted Love" (1981).

[61] To promote the album, Jive Records set up a hotline where fans could leave a message for Spears, some of which received a return phone call from her.

[66] Spears' live comeback and promotional activities for Circus began on November 6, 2008, with a cameo appearance at the Dodger Stadium show of Madonna's Sticky & Sweet Tour (2008–2009).

The song was met with positive response from critics, who complimented its hook and empowering lyrics, deeming it a return of form and a "comeback" single for Spears.

[85] Internationally, it reached number one in Belgium, Canada, Croatia, Denmark, Finland, France, Israel, Norway, Sweden and Turkey, and on the European Hot 100 Singles.

[124] Stephen Thomas Erlewine provided a favorable review, describing it as a "friendly remake of the hedonistic Blackout", but preferred its predecessor for being more "sleek or addictive" than Circus.

[126] While Chris Willman from Entertainment Weekly appreciated the overall production of Circus, he was critical of Spears' recently established pattern of "putting out albums with titles that promise more self-revelation than she's ultimately able to provide.

[34] Writing for USA Today, Steve Jones applauded Spears for being "resilient" and "[knowing] who she is as a singer" and not "[wasting] time searching for artistic direction or overthinking her appeal.

"[129] Alexis Petridis of The Guardian gave a more mixed review, suggesting that Spears "frequently sounds disconnected, even a bit bored" throughout the record, whereas Blackout was a "relentless, risky album made by a woman whose obituary was apparently being prepared by Associated Press.

"[49] A writer for The Independent gave a negative review, opining that Spears' vocal delivery sounded emotionless in mid-tempo and ballad-paced tracks.

[118] Slant Magazine's Eric Henderson shared a similar sentiment, suggesting that the album's "self-actualization" gave off a "hollow" feel through the majority of the record.

[122] Ann Powers from Los Angeles Times felt that Circus served as a "bang-up job" of stating that "Spears is still a young woman trying to manage an impossible situation.

"[119] Writing for NME, Hamish MacBain was disappointed that "Spears is quite simply rubbish at being sexy", adding that Circus is the "umpteenth attempt to turn the perceived chaos of Britney's transition to adulthood – she's 27 next week!

Controversy first arose on December 5, 2008, when Australian music site Undercover.com.au reported a complaint on the lyrical content of "If U Seek Amy" from Leonie Barsenbach, a housewife from Sydney, who stated: "I was astonished and totally taken aback when I heard my 5 and 7-year-old kids walking around the house singing 'F-U-C-K' ...

Spears had previously received criticism from the organization when she used an albino python and a caged tiger during a performance of "I'm a Slave 4 U" at the 2001 MTV Video Music Awards.

[170] Australian tour promoter Paul Dainty denied the allegations,[171] while Spears' manager responded via his Twitter account by saying: "It's unfortunate that one journalist in Perth didn't enjoy the show last night.