Man punches Leona Lewis

A young man punched singer Leona Lewis in the head as she signed autographs and posed for photographs at a book signing session in central London on Wednesday, her spokesman says.

Stuart Bell says Lewis, 24, had been meeting members of the public at Waterstone's bookstore in Piccadilly in central London for about 90 minutes when a man from the line came up and hit her. He was immediately led away by security guards and later arrested by police.

Bell says Lewis, who was launching her new autobiography Dreams, was shaken up by the incident and went to see a doctor as a precaution.

Lewis shot to fame after winning the X Factor reality show in 2006, and her powerful voice has led to comparisons with Mariah Carey and Whitney Houston.

London's Metropolitan police say a 29-year-old man was arrested on suspicion of assault and is in custody.