In May Spears returned to the stage under the pseudonym The M&M's

The single, Gimme More, was officially released on the website of New York radio station Z100.

The 25-year-old recently called on her fans to help her choose the title of her next album.

In February the star was admitted to rehab after being photographed shaving her head, following the collapse of her marriage to Kevin Federline.

Last month the couple, who have two children together, completed their divorce.

Her last single, Do Somethin', was released in 2005 and reached 100 in the Billboard charts in the US and number six in the UK.

Music industry magazine Billboard said the new single is expected to get its first radio play next week.

Spears, who has since admitted she hit "rock bottom" after being admitted to rehab, is one of pop music's most successful artists, selling 31 million albums in the US alone.

In May she returned to the stage in the US under the stage-name The M&M's.