‘My Week With Marilyn’: A vulnerable, believable Monroe | 2½ stars

Watching “My Week With Marilyn” is like seeing an actual, long-lost Marilyn Monroe film: It’s not that great, but the star is mesmerizing.

Michelle Williams conveys the mix of canny manipulation and desperate insecurity that defined Monroe, going well beyond the obvious mimicry that a lesser actress would rely on.

The closest comparison is Cate Blanchett’s portrayal of Katharine Hepburn in “The Aviator” — neither actress looks much like her subject, but she becomes her nonetheless. It’s no wonder Williams is a leading contender for a best actress Oscar.

The film adapts the recollections of Colin Clark, a young crew member on the set of Laurence Olivier’s “The Prince and the Showgirl,” for which Monroe traveled to England in 1956. The troubled movie star clashed immediately with the short-tempered Shakespearean, a battle Clark witnessed up close. Lucky for us, he kept a diary.

“My Week With Marilyn” introduces him as an eager 23-year-old (played by Eddie Redmayne) who boldly pushes his way into Olivier’s company. He’s basically a glorified gofer, until he makes an unexpected connection with Monroe.

Colin is as smitten with her as everyone is, but he treats her like a human being, something no one else seems capable of (or interested in). By the end of their short relationship, Colin has become part therapist, part boyfriend and part personal assistant, giving her the courage to finish the project and impressing the frustrated Olivier (Kenneth Branagh).

Like many movies about iconic figures, “My Week With Marilyn” slips into hagiography — but this time, it’s not the star who ends up idealized. Colin is practically a saint in this story, tirelessly protecting the fragile actress from the many people who mistreat her.

While it’s certainly believable that Clark cared for Monroe and offered genuine friendship, he’s just a little too much the selfless hero here. I don’t know if the same tone pervades his memoirs (Clark died in 2002, so he can’t comment personally), but director Simon Curtis and screenwriter Adrian Hodges could have deepened the character for the fictionalized version.

A similar problem afflicts the other players. All the actors (including Judi Dench, Dougray Scott and Emma Watson) are fine, and Curtis captures the nervous rhythms of a movie set nicely. There’s just not much going on beneath the surface. Branagh, in particular, tries mightily to nail down the elusive Olivier persona, but he’s simply miscast. You never forget who you’re really watching.

That is emphatically not the case with Williams.

(At the Mainstreet, Rio and Town Center.)