The pop group were scheduled to unveil new cut 'Something New' on Friday (October 19), but the track has appeared on the internet days ahead of its official premiere.
The song - which will now get its first radio play on Capital FM today (October 16) - is an upbeat dance anthem, which includes the lyrics: "All I want is something new /Something I can hold on to /I don't want to talk /I just wanna dance."
Girls Aloud will make a special announcement live on YouTube this Friday.
It is thought the group will announce a new Greatest Hits collection and a final headline tour of the UK, after Cheryl Cole revealed the plans at the end of her new autobiography.
Cole also admitted that the retrospective and tour will serve as the girl group's last outing as a five-piece and claimed that they plan to part ways following their tenth anniversary celebrations.
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