In her latest film, The Devil Wears Prada, Meryl Streep plays the fearsomely imperious editor of an influential fashion magazine. So she's had some recent practice at dealing with quaking journalists. Today, as well as interviewing her myself, I've been asked to moderate a question-and-answer session in front of a room full of them. Introducing the woman frequently named the "world's greatest actress" has its pitfalls, and I have to confess that in the press conference, I end up going for the obvious: "Meryl Streep has been synonymous with cinematic excellence for three decades..." But she reacts as though I've struck just the right note and beams graciously. She seems to enjoy the reverential atmosphere - no tricky questions and everyone hanging on the actor's every word.
"I wish Meryl Streep would rule the world," gushes Anne Hathaway, her co-star in The Devil Wears Prada. And it's not just young, overexcitable actresses queuing up to lavish praise. Streep's friend Jack Nicholson has compared her to the "Mona Lisa", talking of her "tremendous enigmatic mystery, with that old Gioconda smile". Clint Eastwood says her skill is in "playing vulnerability without playing the victim". Her contemporary, Diane Keaton, calls her "my generation's genius".
Someone asks how she deals with the accolades. "I don't know how to deal with it at all," she says. "On every film set, it's different. In the beginning they may be intimidated, but then they quickly see that there is no reason to be scared. On the first day of filming when I forget my lines, everybody goes, 'Hmm... the greatest what?' And that happens a lot now." The actor throws back her head, scrapes her blond hair back off her face and laughs a hearty, raucous laugh.
"Acting is wildly overvalued," she tells me when we meet later at a New York hotel. "I just try to do my work and do it well. The whole thing is... I don't feel any different or special. So it all just bounces off me. There is one scene in Prada when I'm waiting for coffee from my assistant, and I ask, 'What happened? Has she died?' If I were an assistant in that office I would have laughed, but nobody laughed because they were all so afraid of her. That is something that I do understand from being a movie star. People tremble a little bit when they are around you. And then if you ask for coffee on the set, the request goes down the chain of command, through several layers of people and each one will say, 'She doesn't like sugar, you have to get Sweet'nLow,' and the next one will say, 'No, she likes Splenda. But does she like hot milk or cold milk?' and I never made those demands. All I asked for was coffee. And it's weird."
Streep's work ethic and diligence are legendary, from learning Polish for Sophie's Choice to playing the violin for five hours a day in preparation for Music of the Heart. But she tosses away the praise with a wave of the arm. "I think it is funny that my reputation is for extensive preparation," she says, "because I am probably the laziest of many actors I've worked with. I'm extremely undisciplined, but nobody wants to believe it."
On the other hand, there's no attempt to underplay her ability. When I ask what she thinks makes her a success, I get a direct answer and steady eye-contact. "A willingness to take risks, go out on a limb and make a fool of yourself. It's about choosing good scripts," she says. "There's nothing like the moment when you first read the script. Suddenly your heart starts to race and you're enlivened or angry. I don't analyse it, I just know the feeling when I get it." Unlike almost every powerful actor in Hollywood, she doesn't have her own production company, so doesn't initiate her own projects. Her favourite films? "I would certainly include A Cry in the Dark, Ironweed, Adaptation and The Bridges of Madison County."
Streep, 57, has won two Oscars, for Sophie's Choice and Kramer vs Kramer. In the latter, she penned her character Joanna's climactic court-room speech herself as she felt it was underwritten (risking the wrath of her co-star Dustin Hoffman with her scene-stealing performance). She has been nominated for 13 Oscars, more than anyone in acting history, although her last win was 24 years ago.
In the Nineties, her form slipped in several films, including Death Becomes Her, House of the Spirits, She Devil and her only action film, The River Wild (actually a spirited change from the intensity of her usual roles). "My husband always says; just keep going. People have a really hard time understanding that we're not in control of our lives. I've never run a production company or been in charge of finding material, I'm just a gun for hire," says Streep of that period. "Actors have lower aspirations than you think. I think they want to keep working and have it be interesting, but we're all human, so not everything works."
In recent years her performances have been consistently strong, from Adaptation and The Hours to The Manchurian Candidate. When she won the best supporting actress Golden Globe for Adaptation in 2003, she professed not to have a speech ready because "it's been, like, since the Pleistocene era that I won anything".
There's already talk of a third Oscar for The Devil Wears Prada. It's not an obvious role for Streep, with no sweeping drama, psychological turmoil or complicated accents. It is a satirical comedy set in the world of high fashion. "I have never been interested in glamour, ever," says Streep. "I am deeply bored by all that stuff."
As the glamorous, dictatorial editor of the fictional Runway magazine, flawlessly coiffed and wearing a white wig, Streep's Miranda Priestly is a woman who personifies style and cares deeply about the intrinsic significance of fashion and its effect in the market place. The actor's own disregard for haute couture would drive her character into a sanctimonious diatribe.
"It's true that I'm wearing very fancy clothes today; this is Valentino," says Streep, smoothing the jacket of her * * brown pin-stripe trouser suit. "I feel much more comfortable dressed in jeans and a T-shirt," she insists. "I wear 60 outfits in the film," says Streep, who confesses that she continues to find the fashion arena something of a mystery. "One of the handbags I carry costs $12,000, which is inconceivable to me. But I'm very, very interested in how people put themselves together and announce themselves to the world, through what they put on their bodies. Whether we choose Birkenstocks or Burberry, it all signifies something."
Prada could have ended up as insignificant froth. The landscape is ostensibly frivolous, compared to many of her classic roles. But it was challenging because she has little in common with her character - or so it would appear. "Actually, my daughter leaned over in a Prada screening and said, 'Mom, it's the real you,'" chuckles Streep.
Inevitably, her characterisation of the scheming Miranda Priestly is witty and funny, but it is also surprisingly poignant. Directed by David Frankel, who made Sex and the City, the film is based on the insubstantial bestseller by Lauren Weisberger, which was a fictional account of her own experiences working for the Vogue editor Anna Wintour. "I wasn't looking at Anna Wintour at all for this character," says Streep, who gives Priestly an American - rather than a British - accent. "It's so uninteresting to copy somebody, I don't know how to do that. I wanted the freedom to make this person up." The movie far surpasses the book in entertainment and substance, with Priestly coming to life as a fully fleshed human being rather than a monster.
"A great deal of this role was similar to a film I made very early in my career, called Kramer vs Kramer." (Streep never assumes you're familiar with her films.) In the 1979 drama, she played Hoffman's estranged wife who abandons the family, then fights for custody of their six-year-old son. "In that film and this one, the audience judges my character very harshly right off the bat, right from the start." The actress, who is prone to dramatic gestures as she talks, sweeps her arm in a circle, then bangs her fist on the table: "BOOM, they've decided - 'bitch'. And then the challenge with both characters is to find the humanity in there."
Streep was also interested in what Prada's story has to say about current attitudes towards dynamic women. "One of the things I admire about Miranda is her willingness to just say directly what she wants, and her expectation that she will get it. That is not viewed in our society as an attractive quality in a woman. I think we really don't like women who dare to try and be powerful. We look much harder at them than the millions of men who aspire to the same positions, and I can't figure that out," Streep says.
"I encounter a lot powerful people in my business and if you watch the movie and imagine that Miranda Priestly is a 6ft 2in silver-haired gentleman in a well-cut suit, there would be a very different reaction to all the things she says - if they were coming out in a baritone voice.
"Everybody says; was it fun to play a villain?" Streep continues. "No. It was not fun to be in this person's body. There was a lot of anxiety in this character. So, maybe I took the pressures that she felt too much to heart. I read the script and I read that there was pressure to replace her in her job as editor. I know how replaceable middle-aged women are in our society, and I felt that, so it wasn't enjoyable being her."
Streep's own home life is highly enjoyable. "We don't know what's around the corner, but I feel like I've been very blessed and I'm happy to be 57 years old." She is married to the sculptor Don Gummer, and they have four children, aged between 14 and 26. "The fame and other aspects of my job do not have any residual effects at home. It has nothing to do with me and my normal family life at all," the actor says. Still, her 22-year-old daughter Mamie Gummer is now an actress, and she and her siblings must have rather more exciting childhood memories than most, as Streep took them with her on location. "When I was filming Out of Africa, my daughter Grace was 18 months old. She rode on her brother's back wearing a beautiful antique dress from the movie. Whenever I think of the film, I think of their beautiful golden heads walking off into the beautiful African sunset." She says home life in Connecticut has always taken precedence over career, which may account for the success of her 27-year marriage (her recipe is "goodwill and a willingness to bend and to shut up once in a while"), but also for the career lull when her children were younger.
Streep grew up in an affluent suburb of New Jersey. Her father Harry worked for a pharmaceutical company, her mother Mary was a commercial artist. From the start, Streep liked to be the centre of attention. "Let's face it; we were all once three-year-olds who stood in the middle of the living room performing, while everyone thought we were so adorable. Only some of us grow up and get paid for it."
As a child, she would use eyebrow pencil to draw age lines on her face, pretending to be her grandmother, "to see what it would look like to get older". As a teenager, singing was a greater passion than acting. She apparently made a big impression in the school choir aged 12, and had ambitions to become an opera singer. At Vassar College, she started out studying music, but hated the theory ("It was all maths..."), switched to drama and completed her degree. She auditioned at Yale's drama school, delivering lines by Portia from The Merchant of Venice and Blanche from A Streetcar Named Desire, and was immediately awarded a full scholarship. "I thought it was really fun, but I didn't really think it was a serious way to conduct your life," she says. "You know, I was a true child of the Sixties; we'd just come through Vietnam, Watergate, all of that, and I thought it would be ultimately self-indulgent to be an actor."
Despite her uncertainties, she moved to New York and took her first film role in Julia in 1977. The next year came The Deer Hunter, followed by Kramer vs Kramer and a string of box-office hits in the Eighties: The French Lieutenant's Woman, Sophie's Choice, Out of Africa, Plenty and Silkwood.
These days, she doesn't like to talk about acting technique, but she said years ago: "I have no idea how it really works and I don't know how other people do it. I see [Robert] De Niro writing in the margins of his script, but I don't know what he's doing. I don't question how do I do it and I don't have 'a method'."
She's working with De Niro in First Man, a comedy in which she plays the US President, a step up from her ruthless Senator in 2004's The Manchurian Candidate. "Women are very well suited to rule the world in future, because of the multitasking they do and their ability to be moving in 15 directions at once. It's the women who behave like men, who focus in that singular way with the blinkers on, who have problems. I honestly think that if women were running the world there would be more investment in peace, because basically as women we do not want to see our children killed.
"As for my prescription for peace in the Middle East?" She pauses, sighs. "No, not today. Maybe I am completely idealistic, but until we see women in equal positions of power in the world, I just think that we are doomed."
Streep is known as an activist and environmentalist and has often talked of "doing something more worthwhile than acting". But she can't seem to stop. "Every time I think this is a silly way to spend my life, I see a performance by another actor and think, 'I couldn't live if I didn't have this in my life.'"
Her next film is Robert Altman's A Prairie Home Companion, written by Garrison Keillor, host of the American radio show of that name. She stars as a folk singer and single mother. "It was really fun to sing. I don't get to do it much. At my house I'm not allowed to; your children can't stand it when you sing."
Lindsay Lohan plays her teenage daughter. Of working with the gossip magazines' favourite cover-star, she says: "Three of my children are older than she is, and I have a certain amount of sympathy for the fact that all the mistakes she makes are made in public and people make millions of dollars off those mistakes. I don't know the pressures on these young women who are famous now, to open their lives to photographers. It just seems that maybe there's an opportunity to say no," she laughs. "But maybe if they said no they wouldn't have careers."
She has spent late summer on stage in Central Park in New York performing Brecht's Mother Courage and Her Children, and she's the voice of the Ant Queen in the animated film The Ant Bully. Other upcoming films include Dirty Tricks, a political comedy with Gwyneth Paltrow; an independent drama, Nine Lives, directed by Rodrigo Garcia; and Dark Matter with Val Kilmer. "I like to be busy and I whine about everything. But I do love working. You think, 'Why would anyone want to see me again in a movie?' I always think I'm going to give up."
'The Devil Wears Prada' opens on 2 October