Clark, played charmingly by Eddie Redmayne, narrates the story as Monroe arrives in Britain to make "Showgirl." Monroe is a bundle of nerves and insecurities, so much so that she has Method acting coach Paula Strasberg (Zoë Wannamaker) in tow.
Olivier (Kenneth Branagh) is not amused by Strasberg's presence. Besides starring in "The Prince and the Showgirl," Olivier is also directing. And he doesn't want any interference from Strasberg on the set.
As it turns out, Strasberg isn't the problem. It's Monroe, who sleeps late, takes way too many medications and shows up late for each day's shoot — a constant irritation to Olivier.
Monroe, however, makes one key friend — the lowly production assistant and diarist Clark. He is overwhelmed by her attention. He's infatuated with her looks. And he's charmed by her vulnerabilities.
And who wouldn't be? Williams brings a humanity to Monroe that captures the iconic star's humor, sadness, grace and beauty.
In one of the most memorable scenes, Monroe and Clark flee to the British countryside, where she uses Clark's family connections to get inside looks at Eton College and Windsor Castle.
At the castle, she talks with an archivist (Derek Jacobi) who shows her some original drawings by Leonardo da Vinci. And as if on cue, Monroe takes on her movie persona, batting her eyes, smiling and asking the archivist childishly if that's the same artist who painted the woman with the strange eyes.
And when she and Clark run into a crowd of people who have learned that the world's most famous woman is roaming the British countryside, Monroe turns to Clark and asks, "Should I be her?" To which Clark responds, "Who?"
With a twinkle in her eye, Monroe says simply, "Marilyn," subtly referring to the vast difference between her private and public selves. Then she strikes a pose against the castle walls as the crowd cheers.
Redmayne, as the smitten young Clark, makes a perfect foil for Monroe. But as Olivier, the well-respected Branagh is curiously unconvincing. Williams revels in Monroe's subtleties, but Branagh makes Olivier into a rather one-note complainer.
Still, like last year's "The King's Speech," "My Week With Marilyn" promises to be a crowd-pleaser. And Williams will probably win over any skeptics who thought it would be folly for an actress to try to recapture the Monroe magic.
She might as well start getting ready for her big close-up on Oscar night. It's a role she was born to play.
"My Week with Marilyn"
Grade: Four stars out of five
Running Time: 101 minutes
MPAA Rating: R