The singer, who is set to release her anticipated new album 'Femme Fatale' on March 17, has not completely finished it.

"[The album] is not done. We're in the middle of it right now. It's a little bit fluid right now. I can't even say at this stage what songs for sure are making it and what songs aren't," producer Dr Luke told Rolling Stone.

He added: "We're working with a lot of producers and overseeing it with her A&R and record label and management and trying to make something cohesive."

Meanwhile, Spears manager denied reports that the star is due to perform 'Hold It Against Me' at the Grammy Awards later this month.

(by Holly Frith)