Scarlett Johansson: How the world fell in love

It's the way she handles that cigarette holder. For a few moments in her new film The Black Dahlia (which opened the Venice Festival yesterday), Scarlett Johansson really does look like a Barbara Stanwyck or a Veronica Lake sprung back to life. Her luxuriant blonde hair is piled on top of her head with hairpins holding it in shape. She doesn't so much speak as pout. She has a languorous, lazy quality about her, at once world-weary and provocative. That cigarette holder doesn't leave her grasp. It is still there between her fingers, even when she is eating.

Johansson is a throwback: one of the few contemporary actresses with the force of personality and distinctive looks that characterised sirens in old Hollywood film noirs. As producer Art Linson says: "She has that look that pulls you right back in time." She is not conventionally beautiful. There is something gangly and coltish about her, a hint of Olive Oyl or Shelley Duvall, but that long face, those big, mournful eyes and that sulky mouth are utterly distinctive.

In Venice yesterday, she held the press enthralled as she sat alongside director Brian De Palma and her fellow actors during the morning press conference for The Black Dahlia. In truth, this isn't Johansson's film. She has a far less showy part than that of Swank or British actress Fiona Shaw (who plays a Clytemnestra-like matriarch with a psychotic streak). Nonetheless, many of the questions at the press conference were levelled at her and she was clearly the cynosure. By early evening, just prior to the official screening of the film, a vast crowd had assembled in front of the Palazzo del Cinema to watch the glitterati troop into the theatre. She appeared to be the one the onlookers were most eager to see.

Film-makers and critics alike adore her. Woody Allen recently called her "sexually overwhelming", explaining that: "It's very hard to be around a beautiful young woman who is wittier than you are."

"It is rare that you find someone who is both as smart and photogenic as Scarlett Johansson," agrees Nick James, editor of Sight and Sound. "Although she is not very big, she is able to convey a feeling of voluptuousness which is incredibly sexy. She has a charisma that is very earthy by comparison with her often chilly contemporaries."

As James hints, there is nothing mannered about her. In her films, you never have the sense that you're watching a showy performance just for the sake of it. Her style is understated and has an air of spontaneity. In other words, she is a natural screen actress.

It is easy to forget just how young she remains. The New York-born Johansson was only 14 when she was cast as the kid traumatised by a riding accident in Robert Redford's The Horse Whisperer. By then, she had already been an actress for six years. Her debut came at the age of eight in an off-Broadway play in which she appeared alongside Ethan Hawke. Even at that age she had tasted rejection. Somebody had suggested to her mother that the very cute Johansson family (she has a brother and sister, plus a twin brother) all went to a commercial agency to audition. To her dismay, the only member of the family the casting agent showed any interest in was her older brother.

"I was devastated. Later, I would go up for more commercial stuff and also be devastated, because it was so overwhelming for a little kid that they didn't know if they wanted me, or, like, a little black boy," she has commented of those early experiences. Nonetheless, she insists that she had a normal childhood and wasn't pushed into performing by overly ambitious parents.

Johansson is still in her early 20s but already has a lengthy filmography behind her. What is impressive is how little dross there is in her CV. Johansson hasn't done huge studio blockbusters or teen comedies but has consistently been drawn to offbeat projects. She'll go where the work takes her, whether it's to Bulgaria, Tokyo or London. She is equally adept in comic roles (for instance, Match Point and Scoop, her two recent films with Woody Allen), as a lonely young wife adrift in Tokyo in Sofia Coppola's Lost in Translation, or even as a disaffected adolescent (opposite Thora Birch in Terry Zwigoff's Ghost World). She can go from playing an ingenue in a Vermeer-inspired period piece like Girl with a Pearl Earring to being a vamp in a latter-day noir. Little, it seems, is beyond her: not even British costume drama. Next month, she will be in Britain appearing alongside Natalie Portman in the Tudor-set The Other Boleyn Girl.

Nor is she a brat. While she is photographed constantly attending parties and premieres in designer dresses, there are no accounts of her trashing hotel rooms or throwing fits because her trailer isn't big enough. When she was travelling abroad to promote her films, her mother often used to be in tow as unofficial chaperone. She is not especially revealing about her private life in interviews. She doesn't make political statements and she is not a special aide for Unesco. As a consequence, an air of slight mystery still clings to her - and this only adds to her allure. Moreover, she has a formidable work ethic and claims never to look beyond the next role.

"I just continue working and hope that I can keep working from job to job, nor do I have some grand plan. I mean when you get older and you start to think about it as more of a career, having to balance an independent film with something that's more commercial, it's still making movies," she commented recently.

Nothing fazes her. She has claimed that the only time she felt nervous in the presence of other actors was when she met Patrick Swayze at a party. Dirty Dancing had been one of her favourite movies as a kid and she was still in awe of Swayze. Aware that he is far from the star he was a decade ago, Swayze was reportedly embarrassed and pointed out that his heyday was a long way in the past. She was so crestfallen that she "slunk away to the corner and cried".

Johansson does not appear to take her own growing fame especially seriously. "People have this idea of celebrity that it is this huge deal," she has said. "I am not trying to be a celebrity - I am just trying to make good movies." Nonetheless, if you judge a star's wattage by the number of vacuous and inane questions she is asked during a press conference, Johansson must be considered right up there with Hollywood's finest.

"To many of us fans, you are a sex symbol. What do you think about that?" an Asian journalist asked her in Venice yesterday. "Aren't you a bit concerned or worried that some of the viewers might focus their attention on your great appearance more than your acting?"

"Erm, I don't think about those things," Johansson purred. "Of course, it's nice to be considered sexy as a young woman in my prime, I guess. But I try not to think about sexiness or sexy scenes." Nonetheless, she has acknowledged that she relished her role in The Black Dahlia, as she got to wear the short-sleeved sweaters and pearls of a 1940s femme fatale. "How can you not feel a sexy dish in that?"

The Black Dahlia is full of self-conscious references to Hollywood crime movies and melodramas of the 1940s. Adapted from James Ellroy's novel, which was in its turn inspired by the notorious Black Dahlia murder in Los Angeles, the film has a morbid core. In 1947, a 22-year-old actress called Betty Short was found in wasteland in LA. She had been cut in half at the waist and the blood drained from her body, her mouth slit in a clownish grin.

This story had a strong personal resonance for Ellroy, whose own mother was murdered in 1958. "The Black Dahlia is an obsessive part of my own life history," Ellroy said yesterday as he shared a platform with Johansson during the press conference for the movie. "This was the first media-manufactured murder in American history. It was also a primer on misogynistic violence."

The key themes are sexual obsession, voyeurism and grief. Brian De Palma directs in a self-consciously baroque fashion. Johansson's character is Kay Lake, a classy blonde with a very chequered past. She is an object of obsession for two cops, Lee (Aaron Eckhart) and Bucky (Josh Hartnett), who are investigating the Black Dahlia murder.

Kay seems to be the antithesis of the murdered girl Betty (Mia Kirshner), and to Betty's lookalike Madeleine (Hilary Swank in Rita Hayworth mode). Whereas they are dark, she is a blonde. She wears white and lives in a beautiful apartment. Only slowly do we realise that she is not as self-reliant as she appears. Johansson describes her as, "This painfully lonesome, woefully romantic woman who just wants to be kept safe from harm."

In one of the film's most unsettling scenes, we see Kay in her underwear, with her back turned in the bathroom. Bucky is gazing up at her from the bottom of the stairs and notices the scars of two letters that have been crudely cut into her back. This woman with so much poise was once tortured by a pimp.

"Kay is not innocent in any way at all," the actress says of her character. "She has created this fantasy life in order to be able to wake up each morning and not to dwell on her horrible past."

Why was the American public of the 1940s so drawn to a case as grim as the killing of Betty Short? "I think that when there are periods of depression, people distract themselves with scandal," Johansson suggests. "We've seen it in the past and we see it right now."

Kay's two admirers Lee and Bucky are more drawn to the dead girl than they are to her. In essence, Johansson is acting against a corpse. Nonetheless, as so often in her movies, she brings a pathos and emotional depth to her character. In among the grotesques and obsessives who occupy De Palma and Ellroy's warped universe, she is the one figure who doesn't succumb to the lure of the Black Dahlia. "She looks like that dead girl. How sick are you!" she hisses at Hartnett when he forsakes her for Madeleine, the Black Dahlia's lookalike.

The Black Dahlia is certainly one of the best movies yet made of an Ellroy story. As the novelist said yesterday: "Twice in my novel-writing career, I've been lucky with film adaptations - first with LA Confidential and second with The Black Dahlia."

Whether or not The Black Dahlia is a high-water mark in Johansson's career, the paparazzi in Venice swarmed around her. She galvanised a festival which began in surprisingly subdued mode. So what now for the twentysomething veteran? Maybe she'll struggle to find roles that extend her. She might be drawn into making bland studio fare. But all the evidence suggests she will be as judicious in her future choices as she has been thus far.