Spice Girls launch stage musical Viva Forever!

Melanie Brown, Geri Halliwell, Emma Bunton and Melanie Chisholm gave the show a standing ovation within a minute of the curtain rising

The Spice Girls have reunited in London for the world premiere of a West End show based on their hits.

All five attended the launch of the "jukebox musical" Viva Forever! which features hits such as Wannabe and Stop.

Written by Jennifer Saunders, it tells the story of a girl band who pursue stardom on a reality TV series.

After the show, the Spice Girls took to the stage, where Mel C thanked the "wonderful" cast, saying: "I think they've done a pretty good job."

Although Sporty Spice (aka Melanie Chisholm), Scary (Melanie Brown), Baby (Emma Bunton), Posh (Victoria Beckham) and Ginger (Geri Halliwell) do not appear as characters in Viva Forever, the plot - in which four friendships are tested by fame - resonates with the Spice story.

The band achieved global fame almost overnight with the release of Wannabe in 1996, but within two years, Halliwell had quit, saying through her lawyer: "This is because of differences between us."

The quintet have since reconciled, staging a comeback tour in 2007, but Halliwell admitted that watching the show "does bring up a lot of feelings".

"I felt a little bit tearful," she told the BBC.

Victoria and David Beckham watched with their sons Brooklyn, Romeo and Cruz. They arrived separately, having been stuck in traffic.

Beckham, who watched the performance with her husband, David, and three sons, thanked Saunders for the script, and paid tribute to her family.

"I love you all," she said, before gesturing to her bandmates. "And well done the girls."

Viva Forever! shares much of its DNA with Mamma Mia! - the hugely successful ABBA musical which has taken more than £1.2bn at the box office since in 1999.

Both shows were produced by Judy Cramer, and both feature a strong female cast, in this case led by Hannah John-Kamen in the role of aspiring pop star Viva, and Sally Ann Triplett as her adoptive mother.

Where the two shows differ is in the strength of the band's back catalogue.

While Mamma Mia! opens up with a triptych of sing-along classics, the Spice show begins with Let Love Lead The Way and Right Back At Ya, two songs from the band's little-loved third album, Forever - the one without Ginger Spice.

In fact, it takes almost 30 minutes to get to a bona fide hit - the Motown pastiche Stop - with most of the big numbers reserved for the second half.

Early reviews in the Guardian and the Independent have both focused on the lack of showstoppers.

"The lyrics are required to drive the action on," noted Alexis Petridis in the Guardian, "and the lyrics of Spice Girls songs are appalling".

Nonetheless, the audience for the premiere - which included Sir Andrew Lloyd Webber, Joan Collins, Cilla Black, Holly Willoughby, Dawn French and Graham Norton - was enthusiastic, with the best reception reserved for a 10-minute megamix performed during the curtain call.

Halliwell noted: "It's mind-blowing when you see something that we wrote in a little, tiny cold studio over 14 years ago, and then this West End cast is singing our songs. We're so proud."

Speaking after the show, Saunders said she "was very pleased" to see it come to fruition after three years of work.

"It's a relief but I hope it won't stop now, because I've enjoyed it so much. I'll probably still call in every couple of weeks and hope they still know who I am."

The cast, meanwhile, said performing in front of the original Spice Girls had been "nerve-wracking and exciting".

"We all stood at half time peering out of the curtains, working out where everybody was," said Hatty Preston, who had all the show's best comedic lines as Minty, a ditzy PA on a reality TV show.

The actress, making her West End debut, said she had grown up listening to the Spice Girls.

"I still hadn't really reconciled myself to the idea that they're actually real people," she told the BBC.

"I think, in my head, they were always just these superheroes that exist somewhere else. And they are the nicest, chilled out, lovely group of girls. It was very overwhelming."

That's exactly the sort of reaction the producers of Viva Forever! will be banking on from their paying customers, if they hope to see the show spread as far as Mamma Mia! - which now has productions in more than 16 different languages.

Outside the Piccadilly Theatre, many of them had turned up to see their idols arrive - chanting "we want Spice" and singing the chorus to Mama over and over again.

Speaking to the BBC, Chisholm said the band's lasting appeal had a simple explanation.

"We were really honest, and we really spoke from our hearts. We loved working together and writing music together, and we feel really lucky that people identified with us."