The Spice Girls musical doesn't have a storyline yet.
Mel B - who was joined in the group by Mel C, Geri Halliwell, Emma Bunton and Victoria Beckham - has revealed producer Judy Craymer is currently working on the plot for the show, tentatively titled 'Viva Forever', after speaking to all the girls individually.
Speaking at the launch of her new computer game 'Get Fit With Mel B' in conjunction with Black Bean Games, she exclusively told BANG Showbiz: "The musical is coming out in 2012. We don't know anything creatively just yet, because they are still in the middle of creating the whole storyline.
"Judy Craymer took down all of the Spice Girls' stories and she is going to create the story she wants to go with. So we don't know what angle she is going for yet."
The 35-year-old singer also revealed she doesn't plan to make a cameo in the production.
Asked about making an appearance, she said: "No. A musical is like, well, it's about me so I wouldn't get involved in it on that level."
Craymer - who produced 'Mamma Mia!' - has previously promised the musical will be a very "exciting" show.
She said: "It is important to me that the excitement, style and humour of the Spice Girls is well represented on stage.
"I want to create a unique Celebration of the band and its music, with its own flavour and joyful message."