Simon Cowell buys Leona Lewis a $5m Beverly Hills mansion

Simon Cowell is so proud of Leona Lewis -- he's buying her a $5m Beverly Hills mansion.

The 'American Idol' judge, 48, splashed the cash because he reckons Leona, 22, needs a base at the heart of America's music industry.

"Simon thinks she is absolutely amazing so he wanted to treat her," a source told Britain's Sunday People newspaper. "He's so pleased with how hard she works and what a massive success she's become.

"Even though Simon is very rich, he's careful with money and doesn't like to waste it.

"Leona's a homely girl and isn't at all flash so Simon got the idea to buy her something practical she would use.

"He sees a bright future for her. He thinks she can become a global star like Shirley Bassey or Whitney Houston."

Leona -- who shot to fame after winning UK TV talent show 'X Factor' -- is the first British woman to get a US No1 since Kim Wilde's You Keep Me Hanging On in 1987.

Leona said of her American success: "Being No1 in America is beyond my wildest dreams.

"I called my family to tell them and my mum burst into tears."