Leona Lewis Leona Lewis

A man was arrested after allegedly punching pop songstress Leona Lewis at a book signing in London, the BBC reported.

Lewis, 24, was signing copies of her autobiography, Dreams, for about 90 minutes Wednesday when "a guy came up and punched her to the side of the head," Lewis' spokesman told the BBC. "Leona's understandably badly shaken and apologizes to the fans she was unable to meet and complete signings for."

According to a witness, "[the attacker] walked up there with the book, she signed it and, as she looked up, he just punched her." Another onlooker said: "She was running out with her hand over her eye and I just saw a man on the floor."

The "Bleeding Love" singer did not seek medical attention but pulled out of a planned Wedneday night appearance on the BBC show The One