My Week With Marilyn (15)

Starring: Michelle Williams, Kenneth Branagh, Eddie Redmayne

Marilyn Monroe had a lambent quality on screen. Her face seemed to glow out at the audience. As much as her physique, it was the way she photographed in close-up that gave her that mysterious appeal. Against huge odds, the brilliant American actress Michelle Williams manages to capture the Monroe mystique. Her uncanny performance lends an extra charge to what might have otherwise seemed a very middling 1950s period piece (albeit one full of excellent character turns).

My Week with Marilyn tells the story of Colin Clark (Eddie Redmayne), a drippy Englishman in his early 20s, ex-public school and Oxbridge, who has a hankering to work in the film industry. It's not an ambition that his father, Kenneth (of Civilisation fame), takes at all seriously. Clark's persistence eventually wins him a job as a third assistant director on The Prince and the Showgirl, the film that Sir Laurence Olivier is about to make at Pinewood Studios with Marilyn Monroe.

Olivier is played wonderfully by Kenneth Branagh. He mimics Olivier's clipped actorly diction, plays up his campness and vanity, while showing his strange mix of vulnerability and drive. The Olivier here may be self-absorbed and prickly, but he knows that Marilyn Monroe has qualities he doesn't possess and wants some of her stardust.

Director Simon Curtis does a fair job of capturing the "Rankery," as Pinewood Studios used to be nicknamed in the 1950s, when the Rank Organisation was busy making its Doctor in the House and Norman Wisdom comedies. The studio is full of technicians in jackets and ties. We catch a passing glimpse of Wisdom in his cloth cap. There is a tremendous scene early on when the cast assemble for a first read-through. Monroe, inevitably, is late and flustered. Dame Sybil Thorndike (Judi Dench at her most emollient) tries to comfort her, but it's clear Monroe feels as if she is on Mars as she sits down with all these eccentric and mannered British actors. For their part, they're utterly bewildered by her adherence to "the method", and can't begin to understand why she needs an acting coach (Zoë Wanamaker's Paula Strasberg) on set with her at all times.

In its lesser moments, My Week with Marilyn resembles a self-conscious British TV drama. It plays up caricatured ideas about Englishness at every opportunity. As we flit from the thatched roof pub where Clark stays during shooting to the library at Windsor Castle or from Eton College to London Airport, it's as if we're caught in a theme park version of England. Not even Working Title at their most shameless in the Notting Hill-era offered quite such a roseate, tourist-eye view of England.

The most problematic character in the film is Clark himself. Curtis and screenwriter Adrian Hodges resist the temptation to portray him as an Ian Carmichael silly ass type of the kind. As played by Redmayne, he is posh but pragmatic. He is continually getting the production out of a fix. What is very hard to understand is why Monroe, then the biggest movie star in the world, would be so drawn to such a chinless wonder.

It's left to Michelle Williams, surely a front runner when the race for best actress awards begins in earnest in a few weeks' time, to lend emotional urgency to the film. Thankfully, she doesn't play Monroe as a victim. Nor does she try to send up cinema's most voluptuous icon. Instead, her Marilyn is febrile, highly strung and playful. By turns, she is open to the outside world and suspicious of it in the extreme. She is surrounded by patronising men. Her husband Arthur Miller (Dougray Scott), a saturnine figure in spectacles, is just as frustrated with her as Olivier is himself. She is only too aware that agents and publicists who seem to care so much for her well-being really just see her as a meal ticket.

That readiness to show a character in her most intimate and vulnerable moments was also there in Michelle Williams's performance as the young wife whose marriage is unravelling in Blue Valentine. The difference here is that she also has to be glamorous in the extreme: to live up to the preconceptions that everyone has about Marilyn Monroe.

If My Week with Marilyn is a triumph for Williams, it is one that was achieved in collusion with the cinematographer Ben Smithard. The greatest compliment that can be paid to him is that his beautifully constructed close-ups of Williams bear comparison with those that Jack Cardiff filmed of the real Monroe in the actual film of The Prince and the Showgirl. It's not just the way he shoots Williams's Monroe that impresses in its richness and graininess, Smithard's use of colour recalls the look of 1950s Technicolor films.

The character acting here is of a very high standard. Julia Ormond's Vivien Leigh is only on screen for a few minutes, but still offers a striking portrayal of an actress who knows her own beauty is fading. She is trying to be stoic in spite of knowing her husband Olivier has chosen Monroe in preference to her. Emma Watson, adjusting to the post-Hogwarts world, has a scene stealing cameo as Lucy, a pert and pretty young wardrobe assistant courted by Clark until he becomes besotted by Monroe. Just occasionally, the film hints at the snobbery and class tensions that riddled the Britain of the era. Clark, we are always aware, is from a background of extreme privilege. Working in films is, for him, slumming it. He is a surprisingly bland protagonist, but with Williams's blazing performance as Marilyn, that scarcely seems to matter.