The pop five-piece, who will make an announcement about their future plans tomorrow, are said to be following in Take That's footsteps by revealing all on a primetime documentary.
Take That - For The Record, an examination of the Brit award-winning boyband's career, aired on ITV in November 2005, drawing over seven million viewers.
A source told The Sun: "There have been ongoing discussions about doing a documentary looking back at the beginning, the height of Spicemania and what happened towards the end.
"It will be full-on nostalgia and a look back at living through those amazing years. It will focus on the Spice Girls as they were, not what individuals are up to now.
"If you thought the Take That documentary was big, you ain't seen nothing yet. Let's not forget they were, and still are, the biggest girl band ever. They even managed to crack America."