Seven years after splitting up, the Spice Girls have announced a worldwide comeback spectacular.

The girl band will kick off a world tour in America. The five - now all in their thirties - will start on 7 December in Los Angeles - the new home of Posh Spice Victoria Beckham and her family.

The group, including Victoria Beckham, Melanie Brown, Melanie Chisholm, Geri Halliwell and Emma Bunton fell straight back in sync, striking familiar poses for the world's media.

The reunion tour is set to hit London on December 15 and take in Madrid, Koln, Las Vegas, Sydney, Cape Town and Buenos Aires among others (scroll to bottom for a list of dates and locations).

Posh said: "My main reason for doing this is for my kids - so they can see what mummy used to do. I'm going to be the cool one in the family for once!"

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They're back! Victoria Beckham, Melanie Chisholm, Geri Halliwell, Emma Bunton and Melanie Brown prepare to announce their comeback in London

Girl power: Melanie Chisholm, Geri Halliwell, Victoria Beckham, Emma Bunton and Melanie Brown in their 1990s glory

David Beckham will be joining the tour as it will coincide with a gap in the US soccer season, his wife said.

"He's going to be on tour with the kids and all of our families. He's so excited about us getting back together," she said.

The tour will certainly be lucrative for the Spices - they are expected to pocket about £10 million each.

All five insisted they are not reforming for the money.

Halliwell declared: "Money is not an issue. We're doing this because it's a once in a lifetime opportunity to be a Spice Girl again. Who would turn that down?"

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Victoria Beckham, who is set to relocate her family to Los Angeles, flies the flag of her future home country

All the world's a stage for Posh

"Why would we want to talk about Take That? We want to talk about the Spice Girls," said a clearly annoyed Mel B.

Mel C chipped in: "Take That have had a fantastic comeback. But the one thing that's very different is that we were truly global. No disrespect..."

They also claimed there are no hard feelings over Halliwell's walk-out in 1998. "We've forgiven her," Beckham said.

"I love all the girls. Yes we argue, but we are like sisters."

Halliwell did not anticipate the significance of getting the girls back together.

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The group wave the Union Jack, once Geri Halliwell's trademark costume

The way we were: the Spice Girls 10 years ago

"It's like organising the G8 summit," she told journalists.

The press conference at London's O2 Arena was attended by the world's media and hosted by actor Richard E. Grant, who appeared in their film Spiceworld.

The girls entered the auditorium hand in hand.

Mel B proved she is still the shoutiest Spice.

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Spice world: the girls prepare to go on a world wide tour

Posh lead the charge in a revealing corset and skinny jeans while new mother Geri opted for a more demure look in a maxi dress.

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Spice to be here: Sporty, Posh, Ginger, Baby and Scary in London

United front: the girls have finally announce their comeback tour

The world's media were treated to a video montage at the 02 Arena, formerly the Millennium Dome, of some of the band's Number One hits.

Geri enjoyed the moment, taking pictures of her fellow bandmates and the crowd with a camera.

The group said they would not be performing at this weekend's Concert for Diana.

Princes William and Harry were said to have asked them to attend the anniversary event.

But the band said they could not take to the stage so soon because Emma was about to have her baby.

Mel C said: "We would have loved to be there this weekend. It's just unfortunate timing."

Victoria said there would be a creche on the tour to accommodate the seven Baby Spices the band members will have between them once Baby Spice gives birth.

Posh said: "We're definitely going to have a huge creche. Our priority is going to be our families. We want to have fun.

"That's one of the many reasons for this, for our children to see what we used to do."

Geri said of the reunion: "Obviously it's nostalgic. But equally, if new fans want to come along, that's fantastic.

"I like to think our songs are universal and they are timeless. Hopefully, the young'uns will like it too."

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The girls are set to step back into the spotlight together

Asked whether it was a comeback, she said: "Where did we go?"

Still, there is a intriguing secret they will no doubt be keen to keep from fans.

They won't be belting out their songs just by Girl Power... but with the help of Computer Power.

For while the showbusiness world eagerly awaits their return, aides closer to them have been less enthusiastic about their vocal abilities.

They are set to go into the studio to pre-record the songs for their tour - in order to mask the failings of their own live voices.

When the girls sing out of tune on stage, the mistakes in their voices are instantaneously corrected - in less than a tenth of a second - by computer to perfect the pitch and tone.

And it is this remastered "virtual voice" which belts out across the arena. The girls' vocals are altered so quickly that it will appear the resulting perfect voices are live and their own.

The system is not miming as such, because they are not just mouthing music to a backing track.

A Spice Girls spokesman was adamant that detailed touring logistics which would cover the use of live vocal enhancement had not yet been discussed, adding: "They all have great singing voices."

All of the Spices, with the exception of Sporty, have seen their solo music careers collapse or come close to failure.

A statement has promised: "Given the band's unique history, you can be sure to expect the unexpected!"

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The Beckhams arrived at Heathrow airport from Singapore ahead of the press conference

Now they are millionaires, aged from 31 to 34, and will soon have seven children between them.

They will hope their reunion follows the success of Take That's, rather than the likes of E17, who recently attempted a comeback.

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Mel B let her hair down the night before the press conference, hitting London hotspot Boujis with new boyfriend Stephen Belafonte

Melanie C, who has enjoyed the most successful solo career, was the last to sign up to pop svengali Simon Fuller's masterplan.

The band's debut single, Wannabe, was released in 1996 and was followed by a string of Number One hits.

The Spice Girls parted ways in 2001, after continuing on following Halliwell's sudden exit from the group.

The Spice Girls have announced 11 world tour dates on their website:

Los Angeles - December 7

Las Vegas - December 8

New York - December 11

London - December 15

Koln - December 20

Madrid - December 23

Beijing - January 10

Hong Kong - January 12

Sydney - January 17

Cape Town - January 20

Buenos Aires - January 24

Ticket details are available from www.thespicegirls.com.