The talk of the town

Hollywood stars' faces have always been their fortune. But these days, says Ryan Gilbey, what they can do with a microphone is just as important

Have you been to hear any good movies lately? These days no animated feature is complete without the vocal contribution of someone from the upper branches of the celebrity tree. It's a trade-off. The film-makers get the prestige of a big star, while the performer benefits from the ego factor: no, of course I don't mind playing second fiddle to the animation by not showing my face; on the other hand, this is proof that I'm famous enough for the audience to know that I'm there without seeing my face.

This wasn't always the case. If it had been, then Pinto Colvig (Sleepy and Grumpy in Disney's 1939 film of Snow White and the Seven Dwarves) would be a household name, and a signed picture of Adriana Caselotti (Snow White to you) would fetch thousands. But if a well-known voice was hired, it tended to be a specialist talent, like the jazz musician Louis Prima in The Jungle Book (1967) or the singer Pearl Bailey in the 1980 film The Fox and the Hound (well, how many other people could you plausibly cast as a character named Big Mama?). Or it would be an actor who would scarcely bring anything more to the film if he were there in the flesh, like Rod Taylor, whose turn as Pongo in One Hundred and One Dalmatians (1960) sounds now like a dry run for his damp dishcloth Mitch Brenner in The Birds (1963).

John Hurt may appear to be an exception – he could be heard in Watership Down (1978), The Lord of the Rings (1978), The Plague Dogs (1982) and The Black Cauldron (1985) – but in fact, he proves the rule. In the flesh, he could slip effortlessly from playing Timothy Evans to Quentin Crisp to John Merrick, and it was exactly this flexibility that made him a perfect fit back in the days when voice actors were required to be heard and not seen. The key word was functional. If you noticed them, then they weren't doing their job properly.

It seems impossible, now that a film such as Shrek can be sold on the strength of its star names, that all this potential was once untapped. Part of the change has come from the new-found crossover appeal of animation: no six-year-old will give a hoot whether Shrek is played by Mike Myers or Michael Portillo, but the difference is crucial to those cocky 15-year-olds who may bother seeing Shrek only because of Myers. Until the rise of series such as The Simpsons and South Park, there was nothing hip about the idea of using celebrity voices. Bill Murray may have voiced the lead part in the adult cartoon Jungle Burger (1975), but that was back in the days before he had a name to trade on.

Now there are few things more credible than stepping up to the mic. Mel Gibson recently demonstrated that the process could be liberating by giving his most energetic performance in years in Chicken Run (2000). But then he may be more sensitive than most about his voice, having had his Australian accent dubbed over for the US release of Mad Max (1979). What better way to exact a belated revenge than by making a mint from that formerly maligned voice alone? Andie Macdowell, dubbed by Glenn Close in Greystoke (1983) and to this day robbed of her Texan tones in the L'Oréal ads, should try it some time.

The key to Gibson's performance was exactly that – it was a performance, not just a voiceover, and not a loan on his celebrity, as his role in Pocahontas (1995) had been. Giving your voice isn't enough: you have to give everything. In Aladdin (1992), Robin Williams doesn't simply provide the voice of the Genie – his physicality is there in the animation, too, as though he swam around in the inkpots and scaled each hair of the brush. Although he is never technically on screen, it's still his most exuberant performance. "What Robin Williams contributed to Aladdin," noted Robert Altman, "could not have been the work of either a director, a writer or an animator. The creativity contained in his work was his alone."

Perhaps it was the liberation of not being seen, or the challenge of creating a character through voice alone, but in Aladdin, Williams rediscovered an energy from his stand-up days that few of his films had captured. As the Genie, we saw him afresh, just as we had found in Kathleen Turner's Jessica Rabbit from Who Framed Roger Rabbit? (1988) a way to enjoy again the eroticism of an actress who had been unable to sustain her own allure. In the beginning was not, as is commonly thought, the word, but the image, and when we have grown tired of that image, animation offers an opportunity to see actors in a whole new light, a whole other form.

Aladdin showed film-makers what could be achieved by casting stars rather than anonymous jobbing actors; Toy Story (1996) took the notion further, by utilising fine performers all the way down the cast list. Below Tom Hanks, you could also find Laurie Metcalf as Andy's mum (a joke: she was mum to another Andy in Roseanne) and Wallace Shawn as a plastic Tyrannosaurus rex that was essentially Shawn's fussbudget character from My Dinner with Andre (1980) with shorter arms and sharper teeth.

Part of the attraction may be that actors can, like Shawn, toy with their persona under cover of animation. So Christina Ricci could further explore her sweetly malignant image by playing a psychotic doll in Small Soldiers (1998), while Woody Allen could send up his neuroses in Antz (1998) and Nathan Lane could flex his warmly poisonous wit as the jealous cat in Stuart Little (1999).

The most inspired vocal casting can create sparks of recognition that bring new layers of meaning to a movie. Disney's cleverest manipulation to date can be found in Mulan (1998), where the casting itself comments on the film's story about a girl masquerading as a male soldier. Two of the butchest roles are taken by the gay playwright and actor Harvey Fierstein ( Torch Song Trilogy) and the actor B D Wong, best known as the camp wedding designer in Father of the Bride. What might have been throwaway in-jokes in a lesser film became subtle endorsements of the film's message: if these actors could pass for macho men, then anyone could change, switch, cross over. Put like that, animation seems the ideal medium for saying the unsayable, though it's more commonly used to cram in celebrity cameos, as on the forthcoming films Dr Dolittle 2 (Lisa Kudrow, Isaac Hayes), Cats and Dogs (Charlton Heston, Alec Baldwin, Susan Sarandon) and Osmosis Jones (Chris Rock, William Shatner).

The only downside is that actors have become so public about their involvement in animation that the audience is robbed of playing "who belongs to those vocal chords?", a game that can be one of cinema's sweetest unsung pleasures – which may be why the delight in Shrek comes not from Eddie Murphy or Cameron Diaz, but from wondering "Who is that actor playing Robin Hood?" and then reading the end credits to find out that, oh, of course, it's... well, go hear for yourself.

'Dr Dolittle 2' is released next week, 'Cats and Dogs' on 3 August