Usher's Fourth Week At No 1

OMG - Usher Makes It Four Weeks On Top In America

Usher has scored a fourth non-consecutive week at the top of the U.S. pop charts.

The R&B superstar's OMG has kept Katy Perry, B.o.B and Ke$ha off the top of the Hot 100.

Perry's California Gurls moves up a spot to two, while B.o.B's Hayley Williams collaboration Airplanes slips to three and Ke$ha returns to the top five at four with Your Love Is My Drug.

American Idol winner Lee DeWyze lands the new chart's highest debut - his rendition of U2's Beautiful Day enters the countdown at 24.