Actress Michelle Williams, playing Marilyn Monroe, is shown in a scene from director Simon Curtis' new film "My Week With Marilyn" in this undated publicity handout.[Photo/Agencies]

The connection between Michelle Williams' acting and her personal life is so strong that even she gets the two confused sometimes.

Making last year's "Blue Valentine," which painfully and intimately depicted the collapse of a young marriage, occasionally seems so intense of a memory to Williams as to be a true one.

"When I look back on my life and I sort of reflect on relationships or anything, my mind folds that one into the mix of the real relationships that I've had in my life," says the actress. "And I have to stop myself and say, 'Oh, no, you did not marry and divorce Ryan Gosling.'"

While delusions of wedding Ryan Gosling aren't necessarily uncommon to moviegoers, for Williams they exemplify the intensely introspective approach she takes to her work.

Going by her latest film, "My Week With Marilyn," it's clear Williams has undergone a shift. After years of predominantly raw, naturalistic films like "Wendy and Lucy" and "Blue Valentine," in "My Week With Marilyn," she's glamorous and radiant. That, too, is telling of an interior change in Williams.

"One thing that I've struggled with, been interested in just as a person, a girl-slash-woman, whatever I am at 31 in this world, is being comfortable with myself," Williams says. "I've just spent a lot of time getting to know that person and getting to like that person, so I haven't wanted to lose touch with that person through lenses like hair and make-up and clothes."

Yet "Marilyn," which opens Nov. 23, is drawing Williams some of the best reviews of her career, and has put her squarely in the running for a best actress Academy Award. Williams' performance somehow manages to evoke a fully-fleshed person, well beyond mere caricature. It's a layered rendering of Monroe: a public, glorious Marilyn; a private and vulnerable actress; and the song-and-dance showgirl of "The Prince and the Showgirl."

The film chronicles the production of that 1957 film, which Laurence Olivier directed and co-starred in with Monroe. The two clashed: an oil and water mix of classical British theater and American movie stardom.

"There's technically an enormous challenge, which (Williams) meets lightly, effortlessly," says Kenneth Branagh, who plays Olivier. "Then she puts that all away to one side, doesn't show off to the audience about it. ... She doesn't indulge in playing Marilyn, she just is. It required her to work enormously hard and then hide all the work."

In a recent interview over afternoon tea at a Manhattan hotel, Williams is refreshingly candid. She's dressed elegantly but simply in a black and white dress and wearing a short, blonde pixie haircut that she has said is a tribute to Heath Ledger— her former partner and father to her 6-year-old daughter, Matilda — who liked cropped hair.

Williams would have more reason than most to be guarded, but she answers questions warmly and pensively. When Ledger died in 2008 (a few months after he and Williams separated), an onslaught of media attention landed on Williams, who has since often been hounded by paparazzi. It's an experience that frequently hovers just outside Williams' words, an unspoken tumult.

Williams was born in a small town in northwest Montana. Though her family moved to San Diego when she was 9, Williams believes Montana "formed me in some fundamental way" and that, although she lives in a townhouse in the Boerum Hill section of Brooklyn, she "will always feel most at home in nature."

In California, Williams became interested in acting after she and her sister performed in community plays. In a nice touch of foreshadowing, she kept a poster of Monroe on her bedroom wall. As Williams' young acting career grew in TV and movies, she emancipated from her parents at age 15. Two years later, she was cast in "Dawson's Creek," the WB teen drama that ran for six seasons and catapulted Williams' fame.

Williams' film career took off with 2005's "Brokeback Mountain." She received her first Oscar nomination (a second would come for "Blue Valentine") for her performance as the rejected wife of Ledger's cowboy.

She's since drawn the interest of directors like Martin Scorsese ("Shutter Island") and Wim Wenders ("Land of Plenty"), but perhaps been most comfortable in independent films ("Synecdoche, New York," "I'm Not There").

She's twice worked with filmmaker Kelly Reichardt in low-budget films notable for their realism: 2008's "Wendy and Lucy," a film about a woman living in poverty with just her dog and a beat-up car, and this year's "Meek's Cutoff," a gritty depiction of life on the Oregon Trail in 1845. Williams slept in her character's car for "Wendy and Lucy," and learned how to drive oxen for "Meek's Cutoff."

"She really likes the chance to hide and just be able to be a person," says Reichardt. "These films have sort of offered her a chance to work while just being able to blend into the world in a way that becomes probably more difficult."

Reichardt said Williams has been sending her iPhone photos of the craft service table from her current film — Sam Raimi's "Wizard of Oz" prequel, "Oz: The Great and Powerful," in which Williams plays Glinda the Good Witch — exclaiming, "We could make a whole movie with this!"

Williams says she's long had an interest "in naturalism, in no shine on anything, no polish, no veneer.."

"What I've hoped for is to have as little separation between the character that I'm playing and the people in the audience — nothing that made the character feel out of reach," the actress says. "'Wendy and Lucy' was, I don't know if it was the culmination, but definitely that was what I was ultimately aiming for."

Whereas she rolled out of bed for "Wendy and Lucy," "My Week With Marilyn" required three hours of hair and makeup every morning.

"In the film, there's a sort of contrast between the American interior, psychological way of working, and the English external, theatrical way of working," says director Simon Curtis. "But in fact, Michelle came at the character of Marilyn in both directions."

Asked when it was that she realized she wanted to act, Williams says, "That's a decision that I make again and again and again." She lists a series of "mile-marker moments": doing her first English accent, finding camaraderie on the set of "Station Agent," making "Wendy and Lucy," working with Gosling.

Of the less certain times, she says, biting her lip, "Some of them I would hate to bring up." The first Oscar nomination, she acknowledges, "stymied me somehow ... I felt like people were watching. I felt like there was pressure where there used to be none."

People are still watching Williams, but it doesn't seem to bother her much anymore.

"I've noticed that now, at 31, my ideas about scenes or dialogue or moments, they come faster," she says. "And I find that I'm enjoying it and that that's not hampering my work, so maybe it doesn't have to be as hard as I was making it out to be for so many years."