The ex-Pussycat Doll is also holding firm against The Wanted, who are this week's second highest new entry with their official Comic Relief single 'Gold Forever'.
Adele slips to three with Jessie J trailing and they are followed by girlband newcomers Parade, who complete the top five with debut track 'Louder'.
Rihanna, Lady GaGa and Wiz Khalifa each fall three places to six, seven and eight respectively.
Meanwhile, Black Eyed Peas steadily climb the chart to number 18 with new single 'Just Can't Get Enough', while Wheatus re-enter the chart at number 31 with 'Teenage Dirtbag'.
Over on the album chart Adele still dominates the top three with both 21 and 19 at numbers one and three, sandwiching a new entry from The Vaccines, who debut at two with What Did You Expect From The Vaccines?
Further down the chart Beady Eye slip six places to 16 with new LP Different Gear, Still Speeding and Alex Turner enters at 29 with his movie soundtrack EP Submarine.
The official chart positions will be revealed this Sunday at 7pm.
Source: The Official Charts Company