Simon Cowell has vowed to ensure Leona Lewis has maximum security in the future, after a man attacked her at a book signing earlier this week.

The Bleeding Love hit-maker was signing copies of her new book, Dreams, at a central London store on Wednesday when Peter Kowalczyk allegedly punched her in the face.

Lewis needed medical treatment for a cut across her temple after the incident and she was forced to pull out of a scheduled promotional trip to Germany on Thursday. Kowalczyk was arrested and subsequently sectioned under the U.K.'s Mental Health Act.

And Cowell, who has guided Lewis' career since she won The X Factor in 2006, is adamant the singer will be better protected in the future.

He tells Britain's Daily Star, "I was stunned anyone would want to attack her. We need to make sure she is protected."

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(This news article provided by World Entertainment News Network)