British girl band The Spice Girls (L-R) Victoria Beckham, Melanie Chisholm, Gerri Halliwell, Emma Bunton and Melanie Brown, pose for the media as they arrive at the Greenwich Royal Observatory in London, June 28, 2007.[Reuters]

"Girl Power" is back with the announcement that the Spice Girls, who topped charts in the late 1990s, are reuniting for a tour and greatest hits album.

Ginger, Sporty, Posh, Scary and a heavily pregnant Baby Spice told a press conference in London on Thursday that the tour would take place in December and January and would be accompanied by a television documentary about the band.

The 11-city tour starts in Los Angeles on December 7 and ends on January 24 next year in Buenos Aires.

"Girl power is back, we're going on the road, we're touring the world," Emma "Baby Spice" Bunton said in a promotional video shown to the press before the five girls appeared on stage at London's O2 arena.

When asked why she dropped her previous resistance to a reunion, Melanie "Sporty Spice" Chisholm replied: "A girl's allowed to change her mind. This is something that we've only seriously started discussing this year."

Geri "Ginger Spice" Halliwell added: "For me it's about celebrating the past, enjoying each other, it's about our fans. It felt the right time -- it's kind of now or never."

The five-member band is the latest in a long line of pop acts to bury past differences and reform, and they will be hoping for success where many others have failed.

The Spice Girls boasted album sales of 55 million during their meteoric career, and hits including "Wannabe" and "Say You'll Be There" topped charts across the globe.

But their success was short-lived. Halliwell walked out on the band in 1998, only four years after The Spice Girls was created, and the remaining band members went their separate ways after releasing the album "Forever" in 2000.

FLUCTUATING FORTUNES

The singers said comparisons with Take That, a British boyband that enjoyed huge success since reuniting for a tour last year, were inevitable.

"One thing that's very different about the Spice Girls is we were truly global," Chisholm said.

Victoria "Posh" Beckham, who wore her hair short and blond, added: "Take That are starting up again. For us we're celebrating the past, we're going to do a small tour and then that's probably going to be it."

Halliwell called the reunion a "one night stand," joking: "So you can enjoy it more, right?"

All now in their 30s, the singers embarked on solo careers with varying degrees of success after the band split.

Three of the five are mothers and Bunton is expecting her first child in the late summer.

"There's a lot of children, and about to be another one, and our priorities are really our families, as much as we want to have fun," Beckham said.

"One of the main reasons why I think some of us want to do this is (for our kids) to actually see what we used to do. We're definitely going to have a huge creche (on tour)," she said.

Beckham has maintained the highest profile since the band broke up, helped by her superstar soccer-playing husband David and appearances at fashion shows and on tabloid front pages.

The couple are moving to the United States where David has signed to play for LA Galaxy.

Meanwhile, Melanie "Scary" Brown largely disappeared from the public eye until a high-profile paternity case involving Hollywood star Eddie Murphy.

Earlier this month a DNA test confirmed Murphy as the father of Brown's newborn baby girl after he declined to publicly acknowledge paternity.