The girl group - now made up of Geri Horner, Emma Bunton, Mel B and Mel C, after Victoria Beckham decided against joining their reunion - gave their blessing for one of their biggest tracks to be sampled on the song 'Spicy' to aid their comeback, but they have fallen victim to hackers who shared the song early.
However, an insider says the song, which is sung by '1999' hitmaker Charli and was produced by EDM newcomer Herve Pagez, is still going to be ''huge'' with an epic music video set to follow its release.
A source told The Sun newspaper's Bizarre column: ''This song has been years in the making. It's really disappointing that it's been leaked at the last minute.
''But people who have heard it seem to be loving it, which is promising ahead of its release.
''Charli sings the verses and the chorus has been mashed up and turned on its head for a really cool dance song.
''It's got an incredible video, which will be out next week.
''Sadly the Spice Girls themselves aren't in it, but it's going to be huge.''
The 'Viva Forever' hitmakers are said to be ''excited'' about the collaboration.
A source said previously: ''The girls gave their approval after hearing it and are all excited about its release.''
It's not the first time the Spice Girls have suffered a song hack.
In 2016, Geri, Emma and Mel B reunited in the studio to pen 'Song For Her', but that was leaked too.
Speaking at the time, Emma said: ''We wrote something and it got leaked and it got stolen which is not great, but we've had nice feedback.''
Meanwhile, Emma - who is nicknamed Baby Spice - previously hinted that she and her bandmates could start writing new material while they are on their reunion tour, which begins on Friday (24.05.19) in Dublin, Ireland.
She said: ''We haven't started writing or anything like that and it would have to be organic.
''So we'll have to see. After the tour maybe, or during the tour I think, especially with us girls. We're always like, 'What's next?' So it could happen. Who knows?''
'No Turning Back' was released on this day (January 3rd) in 2003.
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