Britney Spears' career comeback has experienced a slight setback - her new song Womanizer has had its radio premiere pushed back until the end of the month (Sep08).

The pop star's eagerly anticipated new single was due to hit the airwaves in the U.S. on Monday (22Sep08), but a snippet of the track was leaked online by a radio station in Tennessee late last week (ends19Sep08).

And now bosses at Jive Records' Zomba Label Group have delayed the release of the tune until 29 September (08) at the earliest.

According to online reports, the current mix of Womanizer, the first release from Spears' forthcoming album Circus, was not the finished version.

A source tells E! Online, "The mix was not finalised."

The leaked song has now been removed from the Nashville radio station's website. (c) WENN