HEMPSTEAD GARDENS, N.Y. — Dressed in an oversized night shirt, Naomi Watts moved stealthily across the darkened suburban house where she was shooting her new movie, stepping toward a couch where a teenage actor playing her son lay asleep.

In one swoop the actress leaned over, kissed the boy on the cheek, rested her head on his arm and gently stroked a clump of hair with a motion that also deftly moved it out of the sight line of the camera – an act of soulfulness that also reminded that, at bottom, most moviemaking is just an elaborate game of Twister. As it flickered on monitors out in the garage and eerily lit the Long Island night, Watts’ face evinced a mix of vulnerability and steadfastness.

It’s an expression we’ve seen before from the actress in movies like “21 Grams” and “The Impossible,” in which she played an embattled mother in hard-edged dramas. But Watts’ role in this film – a quirky dramatic comedy called “Demolition” from “Dallas Buyers Club” director Jean-Marc Vallee – is a world away from the tsunami in “The Impossible.”

She plays a stoner employee of a vending-machine company who gets into a complicated relationship with Jake Gyllenhaal’s at-loose-ends Wall Streeter.

Since breaking through as the enigmatic ingenue in David Lynch’s “Mulholland Drive” in 2001 (after nearly a decade of rejection and credits like “The Hunt for the Unicorn Killer”), Watts has been very busy making dramas. A lot of dramas. So many dramas that it almost seemed like too much. Even to her.

So she decided to make a change. In Alejandro G. Inarritu’s recently opened “Birdman,” she’s a Hollywood-turned-stage actress who provides a foil to pretentious on-screen partner Edward Norton.

And in Noah Baumbach’s Toronto International Film Festival premiere “While We’re Young,” which hits theaters next year, she’s a documentary producer who finds refuge in the hip-hop aerobics of Amanda Seyfried’s eager millennial.

Most loopily, Watts plays Daka, a pregnant Eastern European stripper, in Ted Melfi’s new movie “St. Vincent.” It’s a part she not only accents with exaggerated comedy, but seizes an opportunity even most veterans never get: giving guff to Bill Murray.

“I was doing a lot of these roles, and I just started realizing how at the end of the day it’s a lot to take home,” Watts said from her trailer during a break in the “Demolition” shoot. “If you keep working like that, there’s a buildup of darker things in your life. It has an effect on you.”

She paused. “It’s not bad doing a Russian girl who goes around and says whatever she feels like.”

NO IMMUNITY

Actor career shifts can seem like champagne problems to those of us who don’t make a living in front of the camera. But given the pigeonholing tendencies of modern Hollywood, it’s a daunting obstacle for those who do, and perhaps an eye-opener for the rest of us. Watts’ restlessness over her past phase and difficulties in embarking on a new one illustrate how red carpets and romances with Liev Schreiber are hardly immunizations against career complacency and frustration.

In fact, when Watts, 46, was first sent the “St. Vincent” script she thought she was being considered for the part that went to Melissa McCarthy. “I mean, that was the Naomi part, so I just assumed that’s what I’d be asked to do.” That role, incidentally, is of an embattled single mother.

She won the funnier part, though, and wound up even doing some improv, particularly in scenes where she looks to get under the skin of Murray’s curmudgeon. “I was going all out, and possibly too far at times,” she told The Los Angeles Times at the Toronto International Film Festival. “But it was new territory and I just wanted to bust out. I felt like I’d been in chains, like I was a wild animal getting out of this cage.”

Watts added she “cringed a little” when she first saw the film. “Like, here are these two comedy greats and I’m the one bouncing off the walls,” she said. Though the performance has divided some critics with its outrageousness, it’s earned plenty of plaudits; the Times Betsy Sharkey called her “a hoot,” as Watts shuffles in stilettos telling Murray why he’s wrong or why she has it worse than him.

McCarthy, herself going against type in the film, said she finds herself befuddled by these industry distinctions. “People talk about comedy and drama as these separate things, and that’s rarely accurate,” she said. “I think I get my heart broken in every single comedy.”

Melfi himself wasn’t sure Watts could pull it off – even after distributor Harvey Weinstein, who initially approached Watts, endorsed her. Watts said she suggested Melfi watch a few clips from her semi-autobiographical “Ellie Parker” but tried not to give him the hard sell. “I think I’m too prideful after so many years of being rejected,” she said.

That rejection is an animating force in Watts’ career. A friendship with Nicole Kidman led the British-Australian actress to move to Hollywood in the early 1990s. At first she landed little more than bit parts in bad movies before Lynch cast her in a TV series. Even that seemed to go south when the project fell through, before being revived as the “Mulholland Drive” film several years later. Watts was so enmeshed in the world of B-acting she had committed to an Australian movie of the week and nearly missed its Cannes premiere.

“Mulholland” wound up garnering big reviews, and Watts’ serious acting career was on. Less than two years later she was nominated for an Oscar for Inarritu’s “21 Grams,” and rich dramatic roles – as Valerie Plame, as a Russian immigrant in “Eastern Promises” – followed, before this latest shift. “People think of you sometimes as ‘that’s all they do,’ ” she said. “I hope these (new roles) open the doors to a bigger world.

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Still, old habits die hard. In making “St. Vincent,” Watts used some dramatic methods, poring over videos of Eastern European immigrant women talking stoically about partying on YouTube.

With Schreiber’s “Ray Donovan” well-established on Showtime, the couple and their two sons, who live in New York, are spending more time back in Los Angeles, a shift that has evoked some old, uncomfortable feelings. “It does feel like a rat race there and there’s no escaping it,” she said. “In Los Angeles you feel it even on the school playground. I just end up not going out very much.”

There are other signs of the fragility that came from the early rejection. On “Birdman,” because Inarritu was using extremely long takes and very few edits, actors had none of their usual safety nets. “You’re just standing there hoping you don’t screw up and ruin everything perfect from the previous five minutes,” she said of the part, which coincidentally also concerns a Hollywood actress at a crossroads. “Or hoping someone else screws it up so it’s not you.”

Nor do experiments always pay off. Watts took on the title role in Oliver Hirschbiegel’s Princess Diana movie “Diana” last year, but it was pelted by the critics. Some lauded Watts’ performance, but others were less kind – “Wesley Snipes in a blonde wig would be more convincing,” wrote a British tabloid.

The project still rankles. “I was very focused making this transformation and taking on this role which was completely unlike anything related to me, and I got excited by that,” she said. “I did all I could do. I really worked on the script a lot. But I got more worried as shooting progressed, and it suddenly became a film I didn’t want to be a part of.”

With “Demolition,” she is working with a director known for abetting some major career reinventions (Vallee also directed Reese Witherspoon’s upcoming “Wild”). In the meantime, Watts plays the leader of the factionless in the upcoming “Insurgent,” shot a film with Gus van Sant and aims to make a narrative feature with Errol Morris. (For Lynchians: Watts said she would love to work with the director on his Showtime revival of “Twin Peaks,” “but he hasn’t called me yet”).

She turns philosophical, saying she has been waging an internal fight to accept that major changes come slowly, to fend off a feeling of discouragement. “We repeat these negative patterns in ourselves because they feel familiar and familiar can feel right,” she said. “In retrospect I gave so much power to these casting directors.” She gave a small laugh. “I’m still capable of doing that.”