Britney's fourth single from "Circus" was also the planned fourth single from previous album, "Blackout," in the form of the Bloodshy & Avant production, "Radar." Originally due for release in mid-2008, the single was cancelled and promotional CDs recalled, with the announcement that Britney was back in the studio, happier and healthier, working on a new album. Having already charted in many small markets, the track was included on "Circus" as an international bonus track, and was featured on her world tour, being released as the fourth single from "Circus" in May 2009, to cross-promote her Candies endorsement deal.