Ananova:

A man has been arrested after singer Leona Lewis was "punched in the head" at a signing session for her autobiography in central London.

The X Factor star was hit as she signed copies of Dreams for fans, her spokesman said.

The 24-year-old had been meeting members of the public at Waterstone's in Piccadilly for around an hour-and-a-half when a man who had been waiting in the queue lashed out.

"Leona was the victim of an unprovoked attack this afternoon at her book signing," the spokesman said.

"The police were called immediately and medical attention has been sought.

"Leona is understandably shaken and apologises to the fans she was unable to meet and complete signings."

He said she had been happily signing autographs for around 90 minutes when "a guy came up and punched her to the side of the head".

The man is not reported to have said anything to Lewis during the "unprovoked" attack before security officers swooped in.

A spokesman for Waterstone's confirmed the incident took place during the book signing.

"We are incredibly dismayed that the actions of a single person have ruined this event for Leona and her fans," a statement said.

Lewis was "shaken" and bruised on the side of her head and did go to see a doctor following the incident.

A spokesman for Scotland Yard said: "We were called to Waterstone's Piccadilly Circus at 4:35pm to reports of an assault.

"It appears that a male has slapped a female at the location."

The singing star was due to appear as a guest on BBC's The One Show on Wednesday evening but pulled out following the attack.