Some comedians put their faith in punchlines or razor-sharp one-liners, while others believe timing is everything. But, when it comes to making people laugh, the answer could be staring them in the face.

Research has shown the key to comedy is skin deep, with the most successful comedians having similar facial features.

To make us smile before they even start to speak, a comic should have a round face, small forehead, wide nose and big lips.

Large eyes and high cheekbones add to the laughter factor.

Psychologist Dr Anthony Little believes that Ricky Gervais, star of Extras and The Office, has the perfect comedy face, with a combination of features that win over the audience before he cracks his first joke.

Dr Little, an expert in how we perceive facial features, said: "The features most likely to mark out male comedians for success are predominately soft and feminine."

"The characteristics of a feminine face imply that the person may be agreeable and co-operative, which can be causal in our first imporessions of comedians as being friendly and funny."

"In the same way that infants are pre-programmed to respond to the warmth and approachability of a mother's face, soft feminine features put us at ease and encourage us to relax."

"This is conducive to laughter and enjoyment."

The University of Stirling psychologist studied the facial features of 20 of our favourite comics, including Peter Kay, Lee Evans, Jack Dee, Jimmy Carr, Tommy Cooper, Harry Hill and Ricky Gervais.

After looking for common characteristics such as round faces and large eyes, he morphed their features together to create a composite image representing the perfect comedy face.

A mixture of the features of many individuals, the computer-generated face most closely resembled that of Ricky Gervais.

Dr Little then looked outside the world of comedy, to see which public figures might make it on the comedy circuit, should the day job not work out.

Strong candidates for a life of stand-up include David Cameron and Wayne Rooney.

The Tory leader's round, wide face, large eyes and soft features make him an almost perfect contender, said Dr Little, who was commissioned by the comedy club chain Jongleurs.

And while Manchester United player Wayne Rooney has an angular and masculine jaw, these are offset by a round face and snub nose, with the overall effect a boyish appearance which is approachable rather than threatening.

Actor Daniel Craig, the new James Bond, is a good example of someone who conveys both humour and heroism in a single glance.

Dr Little said: "Daniel Craig's face is closer to that of a heroic actor than that of a comedian, yet it does possess some feminine aspects."

"He is well-suited to play Bond since it's a role that demands a little spoof and light-heartedness as well as dashing masculine heroism."

"It is likely, however, that a comedian would struggle to play a heroic role convincingly."

"Due to their appearance, it would be difficult for them to appear believable in situations where dominance and powerful sincerity is important."

"Daniel Craig would be a flop as Bond if he possessed all the face for comedy traits."

He added: "Having found the perfect face for comedy, there may be a perfect face for business and so on."

"There is great potential for further research."