Duchess of Cambridge Kate Middleton, was given the title of "World's Best Grin" voted by 2,045 British people.
On the other hand Victoria Beckham was named the grumpiest celebrity!
According to new research we are at our most miserable aged 29. Worries about work and relationships mean we break out into a grin just 12 times a day.
In contrast, those enjoying a carefree retirement are the happiest with 79 year olds typically smiling 16 times during the day.
And the study made by iWhite bleach-free teeth whitening, confirms that men are the grumpier gender as they are four times more likely to go through a whole day without smiling than women.
But while they are the most miserable, it seems a smile is still the way to impress a man.