Soldier Spice Geri Halliwell

Aug 12, 2007, 7:00 GMT

Geri Halliwell, EPA/Daniel Deme

Geri Halliwell is following a gruelling military training regime to get fit for the Spice Girls tour.

The 35-year-old singer is said to be terrified she won't live up to fans' expectations and is determined to make her performance the best it can be.

A source told Britain's Closer magazine: "Geri is very anxious she won't be up to the tour and so is on a new regime to make herself as fit as a soldier.

"Geri has been working on her stamina because she's worried about the energy it will take to cope with being with the girls again, getting on with everyone and their entourage, travelling around the globe and performing 15 concerts.

"The prospect of performing in front of so many people after having a baby and being in her mid-30s is worrying. She really wants to be at the top of her game.

"She's determined that people won't point to them as 'too old' or girls who've 'had their day'."

Geri, who has a 15-month-old daughter Bluebell, is even depriving herself of sleep in a bid to improve her stamina.

The source said: "She is experimenting with having less sleep, even though she doesn't have to at this stage.

"She wants to train her body and mind to exist on less sleep, to prepare for when she'll need to be sparkling and bubbly with less rest than she gets now."

(C) BANG Media International