London, Aug 26 : Hollywood actress Julia Roberts has the 'Most Genuine Smile', according to a new poll.

While Victoria Beckham was voted as having the Worst Fake Smile.

The stunner held off her fellow Ocean's 11 co-star George Clooney, who came third, which asked 3,000 people and was commissioned by the online bank Smile.

The 'X Factor' judge Simon Cowell came second.

The other best smiles were that of TV character 'Ugly Betty' played by America Ferrera as well as the mysterious smile of Leonardo da Vinci's 'Mona Lisa'.

Beckham piped the United States president, George Bush, to the top spot of having the Worst Fake Smile.

Pop star Britney Spears was recorded as having the third-worst forced smile.

The former Prime Minister Tony Blair managed to creep into the top five worst fake smiles, coming fourth ahead of Motown superstar Diana Ross.

"There are many different kinds of smiles. But the 'true', genuine, spontaneous smile is one where the mouth spreads in a relaxed way across the face and the eyes sparkle or soften, depending on the context and meaning of the smile. False smiles involve only the mouth," The Scotsman quoted Donna Dawson, a psychologist, as saying.

"If you were to cover up the mouth of a 'false smile' in a photograph, you would see that the eyes appear to be dead and expressionless," Dawson added.

ANI