Leona Lewis is still in shock after she was attacked at a book signing in London on Wednesday, her spokesman has said.

The singer was signing copies of her new autobiography Dreams when a man allegedly punched her in the face.

Leona arriving at Waterstones Piccadilly on Wednesday (Splash News)

Tabloid reports have claimed the individual, who was taken into police custody, had waited five hours to meet the star.

Lewis's spokesman said the singer was “shocked” but “okay”.

Fans had been queueing since the early hours outside Waterstones bookstore in Piccadilly to meet the former X Factor winner.

The X Factor winner signing copies of her autobiography before the attack (WENN.com)

Lewis was 90 minutes into the three hour signing when the alleged incident took place.

On fan told the BBC: "My brother saw the whole incident. He [the attacker] walked up there with the book, she signed it and, as she looked up, he just punched her.

"He [my brother] actually heard the impact."

The incident forced Lewis to pull out of an appearance on the BBC's The One Show last night. She was replaced by presenter Gabby Logan.