Emma Bunton has promised the forthcoming musical inspired by the Spice Girls' songs will be "amazing" but said she had been sworn to secrecy about the story.
The mother of two, who returns to the airwaves for her radio show on Heart tonight, said she could not wait to see the show which is expected to open next year.
She said: "It's going to be amazing. I've heard a little bit about the story but it's top secret. We've been in touch with the producer and the writer."
Absolutely Fabulous star Jennifer Saunders is writing the story for the musical which is called Viva Forever and is being produced by the team behind hit show Mamma Mia! which featured music from Abba.
Emma - known for many years as Baby Spice - said all five members of the group stayed in touch and had become even closer as they all had families.
She said: "Now we've all had children there is so much for us to chat about and we keep in touch with emails.
"Now we've got about 10 Spice Girl babies and I love them all. My son's birthday is coming up and that's a good chance for us to meet up."
She also said she "absolutely loved" Harper Seven - the name David and Victoria Beckham chose for their daughter who was born last month.
Emma gave birth to Tate, her second son with fiance Jade Jones, this May. Their first son, Beau, is four years old this month.