It's not that bad being a movie star. . . Multimillion dollar paydays, global adulation. . . Your own trailer. . .  yet many actors insist on getting behind the camera and directing as well. As Richard E Grant adds his name to the long list with Wah-Wah,  Donald Clarke  casts his eye over a very mixed bag of thespian directors

It's not such a bad life being a movie star. Sure, every lump of your cellulite ends up, arrowed and circled, on the cover of Heat magazine. True, you may have to undergo some kind of physical or psychological indignity - eating lots of pies, wearing an orthopaedic shoe, growing an unsightly moustache - when preparing for your next great role. But being paid to peck Helena Bonham Carter's cheek or push Rob Schneider into septic waste is, surely, a pleasant enough condition in which to find oneself. You'd think all those De Niros, Pacinos, Fosters, Gibsons and Eastwoods would be content with their lot. Not so. They will insist upon directing.

The latest actor to meander behind the camera is Richard E Grant.

Feeling, perhaps, that there should be more to life than having students yell "scrubber!" at you each time you wander out for a paper, the star of Withnail and I has directed and written a decent film based on his early life in colonial Swaziland. Starring Gabriel Byrne and Miranda Richardson as the protagonist's warring parents, Wah-Wah, like so many first films by actors, looks like a mechanism constructed to help the director lever some ancient concern off his chest. Jodie Foster used Little Man Tate, as worthy as it was dreary, to ponder her own trials being raised as a child prodigy. Al Pacino exorcised his lifelong obsession with Richard III in the agreeably barmy Looking for Richard.

So, why do these comfortably pampered celebrities feel the need to turn their fixations into films? "Because they can," Kenneth Turan, veteran film critic with the Los Angeles Times, mused a few years ago. "The studios will let them do it, so they do. Right back to Brando, there was a long period where actors felt that what they do is not real work. These actors are on a mission to be taken seriously."

In the silent era, when the various cinematic professions were still being defined, it was not unusual for directors to start out as actors. Both

DW Griffith and Raoul Walsh changed jobs in this manner. Charlie Chaplin and Buster Keaton wielded the megaphone for their greatest films. But as time progressed and the studio system set in, it became more unusual for thespians to take control of the camera. A puzzling new talent such as Orson Welles, already accomplished in any number of fields, might be accommodated (though, in his case, only briefly), but established stars were expected to know their place. Tied into contracts with their respective studios, actors such as Clark Gable or Gary Cooper were without much leverage. Had those stars asked to direct they would, in all likelihood, have been given some Librium and escorted back to their ranches.

Today's powerful free agents are in a very different position. Financiers, eager to placate marketable stars with ambitions to direct, appear willing to support the most dismal-sounding productions. Of course, sometimes the director in question actually deigns to appear in the beastly thing. Johnny Depp's The Brave may have been grimly banal, but, with Depp's cherubic face on the cover, the DVD probably still sold a few dozen units. Any Johnny Depp film, even one directed by Johnny Depp, is a marketable commodity.

Often, however, the star, suddenly self-effacing, wishes to withdraw from the limelight to allow the film to stand or fall on its own merits. Richard E Grant appears nowhere in Wah-Wah. Robert Redford kept himself out of Ordinary People and Quiz Show. This hardly seems fair on the men who put up the money.

Films directed by actors do, it is true, fare extraordinarily well at the Academy Awards (thespians form the largest voting block, remember). Redford's soapy Ordinary People scandalously beat Martin Scorsese's Raging Bull to the best film gong in 1980. Ten years later, Kevin Costner's ungainly Dances with Wolves left Marty's Good Fellas in the dust. And just last year, Clint Eastwood's Million Dollar Baby beat Scorsese's The Aviator, admittedly only an average film, to the top prize. Could Robert De Niro's upcoming The Good Shepherd defeat his old mentor's The Departed at the awards next year? An irony that pungent might drive the shorter Italian-American to suicide.

For all these films' triumphs at the Oscars, it remains difficult for a genuinely successful actor to gain unqualified respect as a director. Woody Allen, you say? Well, yes. But, having established the neurotic Woody persona during his stand-up days, Allen was always in control of his own professional destiny and, anyway, he only gained real superstar status after he began directing himself.

Quiz Show aside, Robert Redford's films have tended to be denounced by critics as stodgy and safe. Costner was heading in the right direction, before The Postman, a post-apocalyptic fiasco of eye-watering proportions, fatally damaged his standing. Clint Eastwood has delivered many highly admired films, though anecdotes from his actors suggest that his uncommunicative torpor on set could barely be described as direction. "As long as the camera doesn't fall over. The shot will do," Kenneth Turan explains.

Oddly, the most impressive films by actors tend to be one-offs.

Charles Laughton, though he spent years trying to put together a production of Robert Graves's I Claudius, never managed to follow up his mighty The Night of the Hunter. Gary Oldman's magnificent Nil by Mouth, a work so searingly naturalistic it makes Ken Loach's films look like science fiction, remains that actor's only picture. This in an industry that allows Joel Schumacher and Michael Bay lengthy careers.

Perhaps the accusations of dilettantism are just too much for the thespian director to bear. Nobody called Leonardo Da Vinci a dabbler, but anyone suffering through one of Sean Penn's more turgid directorial efforts might find that term floating into his or her mind. Actors, critics seem to believe, do not have the rounded minds required to move into direction So, who does? Well, critics of course. When Jean-Luc Godard, François Truffaut and Peter Bogdanovich, all leading film writers of their day, took up directing almost nobody identified them as dilettantes.

Yes indeed. Only we know what we are talking about. Everybody else is an idiot.