Her single Price Tag which features B.o.B. shot to the number one, forcing Mars' 'Grenade' to stay at second place.
British newcomer Jessie J has held off competition from Bruno Mars to score her first number one on the U.K. singles chart. The London-born singer shot to the number one slot with "Price Tag", her collaboration with U.S. rapper B.o.B, forcing Mars to stay at two with "Grenade".
Ke$ha's "We R Who We R" comes in at three, while the top five is rounded out by Adele's "Rolling in the Deep" and Enrique Iglesias' track "Tonight".
Adele managed to hold her own in the albums countdown - her latest offering, "21", held steady in pole position while her debut, "19", is a non-mover at number four. Dance duo Chase & Status' "No More Idols" enter at number two, while Mars' "Doo - Wops & Hooligans" is third and Rihanna's "Loud" rounds out the top five.