A man has been charged with punching singer Leona Lewis in the head during a book signing.

Peter Kowalczyk 29, is accused of assaulting Lewis as she signed copies of her autobiography at Waterstone's in London's Piccadilly on Wednesday afternoon.

Kowalczyk, of south London has also been sectioned under the Mental Health Act, the Metropolitan Police said.

A police spokesman said he would appear at City of Westminster Magistrates Court on October 26.

Witnesses said the 24-year-old star had been signing autographs for about 90 minutes when the incident took place.

They said a man whose book she signed suddenly lashed out, leaving Lewis with bruising to the side of her head.

Security officers stepped in and held the man on the floor until police officers arrived and arrested him.

Lewis was taken to see a doctor as a precaution after being struck, but needed no further treatment.

The star cancelled a day-long promotional visit to Germany yesterday as she recovered from the ordeal.

In a statement, Lewis said: "Thank you so much for your support, it is truly overwhelming.

"Yesterday was a horrible shock and left me extremely hurt and upset. I'm very sorry to those I wasn't able to meet at the signing.

"Thank you again for all of the lovely messages. Love you all."

Rehearsals for her first major UK show are due to begin next week and it is understood Lewis is planning to press ahead with them.

She is due to play the Hackney Empire next month.