Politics, they will say, has become little more than a branch of showbiz. So it should come as no surprise if the lines which have been blurring for years suddenly disappear.

Others might say that the world of showbusiness takes itself so seriously, it's no surprise if it confuses its role with running the world.

Beatty is by no means alone. Chat show host Jerry Springer recently said he was interested in making a move back into politics, and former wrestler Jesse Ventura is now the governor of Minnesota. Will Smith believes he can be president in 15 years' time.

John Street: Bulworth sets high standards for Beatty

And a whole host of other stars, from Arnold Schwarzenegger and Clint Eastwood to Charlton Heston are involved in politics in other ways.

Jerry Springer - too hot just for TV?

Ronald Reagan was, of course, a pioneer in this field, and his influence is still felt. It was he who was he who was known as the Great Communicator, after all.

And both in the US and to some extent in the United Kingdom, politicians' desire to connect with the people has made them adopt the techniques of showbiz.

Showbiz types have had limited success in UK politics - double Oscar-winner Glenda Jackson, now a Labour MP, is hopeful of being elected mayor of London. But the UK's party system is one of the things that has limited the role celebrities can play.

John Street, of the University of East Anglia, who has written about the links between politics and culture, says politicians are "drawing ever more on the techniques and skills of popular culture to present themselves more effectively".

Clint Eastwood, pictured in Rawhide, later becoming mayor of Carmel, California

This gives rise to the argument that, although there is the sense that image is everything and that all that matters is that politicians appear to be the right kind of person, there are political positions that should be taken regardless of how they appear.

And there are also risks for actors who want to get into politics, Dr Street says.

He believes the advantage of being a film star is that one can stand outside and say: "This is the way politics ought to be".

Beatty has not been short on his criticisms of the political system. It it is not clear though whether a film star president would help to counter Beatty's fears that the US is turning into a plutocracy - a system were power is wielded by a wealthy few.

Nowhere clearer has his view been expressed than in the film Bulworth, which he wrote, directed and starred in. Senator Jay Bulworth, who has sold out on his liberal principles to big money, starts speaking truth about the US political system after a nervous breakdown. It is a clear call for honesty in politics.

"But the reality makes that very hard to live that kind of life," said Dr Street.

"In a sense, in Bulworth Beatty has created his own opposition - he has to match himself against what he said or implies in the film. It's a tough act.

Hugh Grant meets actress-turned-MP Glenda Jackson

"I'd rather be fighting the Republicans than my cinematic image, I think."

He said the real problem with being a political representative was that it was "very hard to be honest in the formal moral sense which people have in personal relationships, for example".

The kind of popularity that film stars or chat show hosts have - that they are men or women of the people - is very close to the kind of popularity that politicians crave, said Dr Street.

"But it's strange that the power they have as chat show hosts or film stars is probably greater than what they would ever have as politicians."

The e-cyclopedia can be contacted at e-cyclopedia@bbc.co.uk.

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