Edinburgh Festival `99: We'll cover you in poses

They don't aim to flatter, but from Madonna to Elton John, the stars are queueing up to have their songs covered by Supergirly

If you were able to give one of your most despised pop stars their final comeuppance, who would it be? Those "bastions of girl-power" the Spice Girls? Robbie Williams and his don't-you-just-love-me grin? B*witched? Or Britney Spears? She did, after all, invite the whole world to "(Hit Me) Baby One More Time".

But rather than resort to violence, Australian double act Supergirly, aka Louise McClatchy and Jai Simeone, have decided to take Britney, Robbie and friends to task in a subtler manner. Dressed in satin and sequins that would make Julian Clary blush, Supergirly perform covers of bubblegum pop bands while highlighting the idiosyncrasies that make them so, well, irritating. If Spiceworld is a place where stack heels and Margaret Thatcher reign supreme, then in Supergirlyworld, Britney Spears is 39, Robbie Williams is a "prat"and Martine McCutcheon's "Perfect Moment" is her "Final Moment". All Saints "Never Ever" is reduced to an indecipherable nasal drawl and the Spice Girls' "Wannabe" is rendered in a horrendous girlie squeal.

And they don't just stop at contemporary pop. Supergirly have managed to turn excerpts from Grease into an X-rated medley, while Orphan Annie's "The Sun Will Come Out Tomorrow" is transformed into a portentous ode to mothers: "Your Son Will Come Out Tomorrow." Even Dusty Springfield doesn't escape unscathed ("He Picked Me Up In A Pizza Van"). Nothing is sacred in Supergirlyworld.

By rights, they should have scores of enemies. But recent developments have shown the opposite to be true. It appears that no self-respecting pop act is complete without a Supergirly cover.

"Most of them can't wait to see what we come up with," says Simeone. "Boy George was the first to ask. We did `Karma Chameleon' at a party where we knew he would be. He just hid under his table and shouted `You bitches!' We've been friends ever since."

Then last year, Sir Elton stepped in. "He invited us to his house in Windsor and said that we could take the piss out of him," says McClatchy. "Now he's booked us for a party in October and he's offered us his Lion King song to `work on'. What a lovely guy!"

The Pet Shop Boys are now among those clamouring for the girls to cover them, they've performed at Martine McCutcheon's birthday bash and earlier this year they were invited to perform at Madonna's party in London. "But she doesn't know that we take the piss out of her," says McClatchy. "We were warned not to sing any of her songs. Imagine the tantrum."

McClatchy and Simeone hail from acting and dance backgrounds, but both had been dabbling in music when they began working together. They first met in Australia when Simeone auditioned to be in McClatchy's band. "She didn't get the part, but I happened to remember her phone number when I was setting up my next band," remembers McClatchy. They ended up with a "semi-serious" act that largely performed covers. "We started singing together at restaurants to get some money together," she says. "I announced that I was going to London and she said she would come with me."

The idea for Supergirly dawned on them when the the pair were messing about during rehearsals.

"We were doing these covers - Michael Jackson, The Pointer Sisters and Bonnie Tyler - and I just started to change the words. After a while we showed other people, and the more we adjusted the words, the better was the response."

Indeed, the Supergirly formula is so simple that you'll kick yourself for not having thought of it yourself. A certain amount of singing and acting talent is needed, of course. Then all you need to do is order the pop songs - essentially a backing track - through a production company who send them out through the post. All that remains is for you to adjust the words, hone your act and you're off.

"With some, you don't even need to change the words," interjects Simeone. "They are stupid enough already."

After a successful West End tour with Lenny Beige, Supergirly now have television production companies vying to sign them up. According to copyright laws, permission from the artists is only necessary when they perform on radio and television. "Most of the artists have given us permission anyway," remarks McClatchy, adding: "Mind you, if we want to do Steps on TV, we would be better off asking the Bee Gees."

But McClatchy and Simeone are keen to point out that this is not simply karaoke. "We've studied these bands for a long time and we actually like a lot of them. All we are saying is that they shouldn't take themselves too seriously. But if they don't like what we don, well, never mind.

Supergirly World! is at the Gilded Balloon, Venue 38 (0131- 226 2151), 8.45pm to 29 Aug