[Firewire]

Britney Spears suddenly collapsed to the floor during a recent rehearsal, sources have claimed.

The 'Toxic' singer, who is currently on the European leg of her 'Circus' tour, was apparently practising moves for her new songs when she lost consciousness and fell to the ground.

An insider told the National Enquirer: "She collapsed when the dancers went to put her back on her feet. She fell to the floor and landed on one of the dancer's legs."

The 27-year-old star apparently mildly injured herself in the fall. The source said: "The dancer's tennis shoe smacked Britney in the chest and on the face. It hit her chest with such a force that it caused a four-inch bruise."

Low blood sugar levels have been blamed for the singer's collapse. The source also said that the star's busy life contributed, saying: "Her schedule has wreaked havoc on her body."

Forbes magazine recently announced that Spears ranks third in the highest-paid celebrity list. She has reportedly earned $35 million (£22 million) in the past year.

DS

I hope she is ok.