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 SpiceGirls` 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 SpiceGirls 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."