Leona Lewis has been forced to return to the United Kingdom from America over fears she was being stalked, according to reports.

A man, described as a “crazed fan”, has apparently been spotted on several occasions outside the former X Factor winner's house in the Hollywood Hills.

Leona has since returned to the UK while security is increased at the £11,000-a-month property.

“Leona had just gone to the shops to pick up some bits and pieces and was followed all the way back home by this man,” a source told the Daily Mirror newspaper.

“She was completely unsettled by this and was pretty relieved to get back to the house safely. But when she looked out of the window later the man was still there, staring right at her.

“It freaked Leona out big time. She feared she was being stalked.”

Leona was already said to be unsettled living at the property, which is meant to provide a base for the star while she records her new album.

The source added: “She’s had new electronic gates put in and CCTV installed which links directly to the local police, station.

“Hopefully that’ll put her mind at ease slightly.”