London  - British singer Leona Lewis was said Thursday to be still shocked, but otherwise "okay," after being punched in the face by a 29-year-old man while signing copies of her autobiography.

The man was arrested after the incident late Wednesday in a central London bookshop where the 24-year-old singer was publicising her forthcoming autobiography "Dreams."

Her spokesman said "a guy came up and punched her to the side of the head" after she had been signing copies of the book for a long queue of fans for an hour and a half.

"He walked up there with the book, she signed it and as she looked up he just punched her," the spokesman said.

The man was promptly overwhelmed by security staff and Lewis hastily left the store. She cancelled a later television appearance.

Lewis achieved overnight fame in 2006 by winning the X Factor casting show, and going on to have the chart-topping hit Bleeding Love. (dpa)