If the show proves successful in their native UK, Victoria Beckham, Geri Halliwell, Emma Bunton, Melanie Chisholm, Melanie Brown and their former manager Simon Fuller have committed to take the show national which could line the girls pockets even further.
"London is a great starting point. We're all so proud to be British. We're hopeful this will be the start of something big," Victoria said at yesterday's launch event in London.
Mel C said the musical will be another push for Cool Britannia, the '90s movement that the Spice Girls helped popularise.
"If we can fly the flag for Britain, we'd love that to a Mamma Mia! It would be nice if it made us a few quid too!"
If you think $7 million is just a few quid, Mel!
Reuniting for the first time in public since their farewell tour,
the group's appearance at the launch was a short one.
Victoria ditched her former band mates at the afterparty to fly back to LA.
"I'd love to stay and hang out with the girls but I'm desperate to see her [Harper] before she goes to bed," Victoria told The Daily Mirror.
"I have to race home for bedtime."
The pop star-turned-fashion designer tweeted her fellow Spice Girls though, thanking them for the day.
"On my way home! Thank you @MelanieCmusic, @OfficialMelB, @EmmaBunton, @GeriHalliwell for an amazing day!"