Unreleased Britney track is a big hit

It seems Britney Spears doesn't even have to release records for them to become hits anymore - an internet download of lost track (I've Just Begun) Having My Fun has become a hit on Apple's iTunes site.

Fans' speculation that the tune is a new track to be added to Britney's upcoming hits compilation has sparked interest in the song - even though it's over a year old.