keira's royal appointment
Rumours are flying that Keira Knightley is set to play Diana Spencer in a major new biopic on the ill-fated 'People's Princess'. Helen Mirren has been approached about playing Diana's mother, Francis Shand Kidd, and the film is set for release in 2011, which would have marked Diana's 50th birthday.
If Knightley, who's now 25, does end up playing Diana she may need to cover her button nose with a more appropriately heroic prosthetic hooter, but will also face a more complex and intractable problem. Because actors who play characters either still alive or very fresh in the public memory must tread a fine line between interpretation and impersonation.
When Knightley, for instance, played Diana's 18th century ancestor Georgiana Cavendish in The Duchess two years ago, she was free to create an entirely fresh and original character.
But Lady Di was no shrinking violet when it came to the cameras, and her wavering voice and superficial diffidence and that trademark flirty upwards glance will have to be addressed in some fashion by whoever plays her.
It's a problem that Hollywood traditionally side-stepped with the application of raw star power. When James Cagney starred in Yankee Doodle Dandy, the brilliant 1942 biopic of song-and-dance man George M Cohan in 1942, for instance, Cohan was still alive and his voice and face well known. Cagney sounded about as much like him as Donald Duck, but it was Cagney so no one cared and the film won a couple of Oscars.
The same was true of Jimmy Stewart, who remained unshakably himself when starring in The Glenn Miller Story, and also got away with it.
But these days audiences are rather more demanding, and the ubiquity of TV and endless celebrity interviews makes us all experts on the faces, voices and gestures of the rich and famous. So actors playing celebrities have to face up to this new challenge, and they do so with varying degrees of success.
Keira Knightley could do no better than to take a leaf from the book of her potential co-star in the forthcoming Diana project, Helen Mirren, who did a seamlessly skilful job of playing Elizabeth II in Stephen Frears' 2006 drama The Queen.
Somehow, without getting excessively caught up in the cut-glass accent and stiff public persona, Mirren managed to simultaneously persuade us that she was both Queen Elizabeth and a flesh-and-blood woman. So good was she in fact that many who'd previously dismissed the woman as a fusty relic began to look at her in a new and sympathetic light.
Mirren's co-star in The Queen, Michael Sheen, has made something of a career speciality out of playing Tony Blair, and he does it exceedingly well. But his range is wider than that, and he perhaps proved it best in Ron Howard's Frost/Nixon (2008).
Based on the famous face-to-face TV interviews between TV personality David Frost and Richard Nixon, the film required Sheen and Frank Langella to transform themselves into the chat show host and the former US president.
Langella was wonderful as the rumbling and lugubrious Nixon, but Sheen did a remarkable thing to take his performance beyond mere impersonation. He made the trademark Frost whine a kind of public voice that was only put on when the cameras rolled, and this tactic allowed a real and believable character to emerge.
One of the most difficult historical figures to raise above the level of caricature is Adolf Hitler. Many actors have tried and failed to make him anything more than a rabid lunatic, but in Oliver Hirschbiegel's Downfall (2004) Swiss actor Bruno Ganz gave us a much more unsettling and rounded dictator.
The film dealt with Hitler's last days in the bunker under Berlin, as the Allies closed in on the city above and the Fuhrer made elaborate plans with imaginary armies. But he also spoke warmly and deferentially to his secretaries and loved to listen to the singing of Josef and Magda Goebbels' children. His voice at times seemed hypnotic, and Ganz's many mooded Hitler was much more disturbing than the spittle-spewing ranter of yore.
In The Life and Death of Peter Sellers (2004), Australian actor Geoffrey Rush faced an equally stiff challenge. Because, apart from embodying the bewildering number of characters Sellers hid behind during his career, from Inspector Clouseau and Dr Strangelove to Chauncey Gardner and Fu Manchu, Rush also had to tackle the enigma of who Sellers might have been himself.
An immature, mother-dominated misogynist, if the film is anything to go by, but Rush had Sellers' shuffling mannerisms down to a tee.
Truman Capote had been dead for over 20 years by the time Philip Seymour Hoffman came to play him in Capote (2005), but the author's high- camp mannerisms would have been well known to audiences from TV interviews.
Hoffman managed to incorporate the distinctive Capote tics, but also got beyond them to the sensitive and wounded but profoundly ambitious man beneath.
Within a year, English actor Toby Jones did arguably as good a job in another Capote biopic, Infamous.
Sometimes, bad casting does an actor no favours. John Voight, for instance, looked perfectly ridiculous in the title role of the 2005 mini-series Pope John Paul II, and sounded more like Bela Lugosi than the late Polish pontiff. Other times an actor's portrayal of a famous person deserves a better film: in W, for instance, Josh Brolin's performance memorably captured George W Bush's jokey likeability and underlying bewilderment, but Oliver Stone's film was not an especially insightful biopic.
One of the very best celebrity screen portrayals of recent years, though, was Christian McKay's mesmerising turn as Orson Welles in Richard Linklater's 2009 drama Me and Orson Welles. McKay was a budding English stage actor with no film experience when Linklater saw him play Welles in a one-man show, and the director insisted on casting him in his movie in spite of studio opposition.
In Linklater's film McKay played Welles as a young impresario on the point of taking Broadway by storm with a revolutionary production of Macbeth, and the actor caught perfectly the beguiling mix of arrogance, charm, high-handedness and bluster that was Orson Welles.
So if Ms Knightley does take on Diana she'll have plenty of good celebrity portrayals to inspire her.
And she's not the only young actress taking on such a challenge: Michelle Williams is currently playing Marilyn Monroe in a film called My Week with Marilyn that co-stars Kenneth Branagh as Laurence Olivier and dramatises the making of the 1957 film The Prince and the Showgirl.
Williams has apparently been staying in character between takes, and if she manages to get beyond the Betty Boop voice to the real woman, it will be a considerable achievement.