The Circus Starring Britney Spears, commonly referred to as the Circus Tour, was the seventh concert tour by American entertainer Britney Spears. It was launched in support of her sixth studio album, Circus (2008). Rumors of a tour arose as early as October 2007, however, nothing was confirmed until December 2008, when the tour was officially announced, with North American and European dates revealed. The stage was composed of three rings and set in-the-round to resemble an actual circus. Fashion designers Dean and Dan Caten created the costumes. A giant cylinder screen was set above the stage to showcase videos and backdrops. Effects were provided by Solotech. Magician Ed Alonzo joined Spears during the second act. The setlist was composed generally from her albums In the Zone, Blackout and Circus. Spears announced she would tour Australia for the first time in June 2009.

Circus is the sixth studio album by American singer Britney Spears. It was released to coincide with her 27th birthday on December 2, 2008, by Jive Records. Transitioning from the "darker and more urban" themes of her fifth studio album Blackout (2007), Spears wanted to make her next project "a little bit lighter". She recorded much of the album between March and September 2008, after being involuntarily placed under a conservatorship earlier that year, following her highly-publicized personal struggles in 2007. 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. Their efforts resulted in a primarily pop and dance record, whose lyrical themes addressed fame, infidelity, and infatuation.