Britney Spears' 'Till the World Ends' Hits Highest Debut on U.S. Pop Charts

 Britney Spears has scored her fifth highest debut on the U.S. pop charts with a new song co-written by Ke$ha. The "Toxic" hitmaker's "Till the World Ends" has entered the new chart at 20 thanks to sales of 117,000 downloads in just three days.

The track was rush-released after it leaked online. Spears' last hit, "Hold it Against Me", debuted at number one on the Hot 100 countdown seven weeks ago.

Meanwhile, the pop world's new queen Lady GaGa scores a fourth week at the top of the charts with "Born This Way". Cee-Lo's "F**k You (Forget You)" holds at two for a third consecutive week, while Rihanna rounds out the new top three with "S&M".