The Spice Girls bandmates have collaborated on a cover version of 'I Know Him So Well' for Mel C's new album Stages.
Bunton described singing together again on the new track as "amazing and emotional".
Stages, Mel C's sixth solo studio album, will be released on September 9.
The project features "a collection of songs from the theatre that have been important to Melanie at various stages of her life".
Mel C recently told Digital Spy that she wouldn't rule out another Spice Girls reunion following their performance at the Olympics closing ceremony.
Photo gallery - Olympics Closing Ceremony:
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