Former Spice Girl Emma Bunton said the group had an "emotional" moment when they read the script of the musical based on their career.
Comic Jennifer Saunders has written the show, provisionally titled Viva Forever, which is based on the girl group's songs.
It is the idea of Judy Craymer, who had a worldwide hit with Mamma Mia!, which is based on the hits of Abba.
Bunton said stories that Mel B and Mel C had fallen out over the show were "ridiculous".
Speaking on her Saturday Show on Heart FM, she said: "This is not true at all. In fact, we've been getting very involved. The amazing Jennifer Saunders is writing it and we had a little read-through the other day. All I can say is that Mel C and I got a little bit emotional."
The Spice Girls had 10 top 10 hits in the UK over four years and sold more than 75 million records worldwide.
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