"Dance" Music (25 Questions) by BruceM

Question 22

Billboard described the 2011 song "Till the World Ends" (chorus: "Keep on dancin' till the world ends") as a cross between Usher's "OMG" and Baltimora's "Tarzan Boy." Rolling Stone described it as "sky-sucking synth streaks, a beat that sounds like blimps fucking and a thousand shirtless drunken sailors chanting along on the chorus."

Who sang "Till the World Ends," off her seventh studio album, Femme Fatale? (She's only six years older than Kesha, who wrote it.)

Britney Spears