"Circus" is a song by American singer Britney Spears. It was released on December 2, 2008, through Jive Records as the second single from her sixth studio album of the same name. Written by Dr. Luke, Claude Kelly and Benny Blanco, "Circus" is a metaphor for the public's perception of Spears' life. After she listened to the track for the first time, she felt inspired to create an album and a tour with a circus theme. "Circus" is an uptempo electropop and dance-pop song with elements of pop rock and "half-rapped" vocals. The song's lyrics talk about being an entertainer and putting on shows.

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.