That perfect smile of Catherine, the Duchess of Cambridge, is a thing of envy and the talk of the town, not only in Britain but in the U.S. and Canada too. Now, however, the secret of that much-fancied smile is out. Apparently, a French dentistry expert is behind her perfect "imperfect smile".

The French dentist, Didier Fillion, specialises in moulding an individual's mouth to create an imperfect look. Fillion is something of a pioneer in the field and is based in Wimpole Street. He doesn't just whiten and straighten teeth. He does what he calls "micro-rotations" and created Kate Middleton's (the Duchess) naturally healthy smile by attaching invisible braces to the back of her teeth, making them look natural and charming, despite their imperfections.

"You know why they look so good? Because they are not absolutely aligned," Bernard Touati, Fillion's colleague, was quoted as saying, in Times magazine.

Micro-rotation is done by grinding and polishing existing tooth enamel or by adding porcelain veneers and it is neither inexpensive nor quick. Kate's smile would have cost anywhere between £4,000 and £11,000 and taken anything from six months to two years to finish.

The dentist has neither confirmed nor denied reports of the Duchess being his patient. However, his celebrity patients already include English model Kelly Brook, actress Sadie Frost and fashion designer John Galliano.

A French dentist is believed to have shaped Kate's perfect smile.Reuters
Kate Middleton was undoubtedly the star of the year as she moved from being a commoner to a member of the Royal Family.Reuters
The Duchess of Cambridge watching the procession pass at the Order of The Garter Service in Windsor, England.Reuters
Kate Middleton watches the procession pass at the Order of The Garter Service in Windsor, England.Reuters
Kate MiddletonReuters