Zoë Wanamaker: The girl can't help it

"Is that black-and-white or colour?" demands Zoë Wanamaker, jabbing a finger at the photographer's camera. Then she turns to me with panic in her eyes and a nervous half-smile on her unmistakable, wide, thin mouth. "That sounded terribly aggressive, didn't it?" she says.

Ten minutes later, we're in a small meeting-room at the National Theatre to talk about her role in the smart-mouthed newspaper comedy His Girl Friday, for which she is winning rave reviews. Wanamaker's relief that her ordeal in front of the lens is over is palpable. "I hate having my picture taken," she declares emphatically and with the addition of an expletive, settling herself opposite me with her pre-packed sushi lunch. Not that she has much to worry about in the looks department. Wanamaker, 54, may not have the regular features of an obvious beauty, but her feline eyes twinkle with humour and intelligence, and her luminous skin is remarkably unlined. She's slight and sprightly, and her spiky hair is expensively highlighted. And then there's that distinctive voice - rich, warm, with a huskiness that may be partly the result of the little brown roll-ups she smokes. In conversation, her refined eloquence is seasoned with some surprisingly salty language and a wicked wit.

Wanamaker's latest return to the National - she has worked there under every artistic director since the building opened - comes hard on the heels of her success in the BBC sitcom My Family, in which she plays the middle-class mum Susan Harper opposite Robert Lindsay. "I finished filming My Family in March," she says, "and then I had about three weeks to get my act - and my life - together before starting work here. So it's all been a bit of a scramble really."

To judge by her packed CV, maybe she likes it that way. She has worked extensively in classical theatre in the UK and on Broadway, and has appeared at leading new-writing venues such as the Royal Court and the Hampstead Theatre. Television credits include her extraordinary performance as the wife of a serial killer in the first series of Prime Suspect, the romantic drama series Love Hurts with Adam Faith and the BBC adaptation of Gormenghast, as well as four series of My Family. Nicholas Hytner, the NT's new artistic director, recently made her a National Theatre associate. It means that Wanamaker will have input into the NT's artistic policy, along with the likes of the playwrights Patrick Marber and Mark Ravenhill, the directors Declan Donnellan and Katie Mitchell and her fellow actors Simon Russell Beale, Adrian Lester, Helen Mirren and her co-star in His Girl Friday, Alex Jennings. "Some really cool people are doing it, so I feel very proud of myself," she half-jokes delightedly. "There's always a great atmosphere here. I love it."

His Girl Friday, newly adapted by the playwright John Guare, conflates Ben Hecht and Charles MacArthur's 1928 play The Front Page with the 1940 Howard Hawks movie from which Guare's version takes its name. Hawks's film, starring Cary Grant and Rosalind Russell, cranked up the sexual tension by turning The Front Page's Chicago newspaper man Hildebrand Johnson into the female ace reporter Hildy - the role Wanamaker is now tackling on stage. She says she knew before she'd even finished reading Guare's script that she wanted to do it. "I just thought - this smells good. It smells fun - and I think theatre should be fun. I mean, what's the point of being in something if you can't have a good time?" But she has had some demanding roles - surely it wasn't exactly fun playing, say, Sophocles' tragic heroine Electra? "Yes, it was. I was getting my rocks off. Excitement and adrenaline are such powerful drugs."

By comparison, you would think working on the cosy sitcom My Family would bore her. "My Family? That's never enjoyable for me," she says, then laughs uproariously. "No, that's not true. We have a jolly time of it. But you get a script on Friday and you record it on Thursday, and it's really hard work. It's like being at school, you have to learn lines constantly. You can never sit back and play with it. That's me - I'm a slow worker, a slow burn. That's why I'm more comfortable in the theatre." And then, of course, there's the inevitable loss of privacy that on-screen exposure brings. "Yes, the power of TV and film is massive. It is a bit of a shock when it happens to you. And I have a very cynical attitude to the press. Very." She pushes her sushi aside, saying, "I can't eat and talk at the same time, I'll have a cigarette instead." She rolls one deftly, lights up and regards me thoughtfully through the smoke. Given her distrust of journalists, what's it like playing one in His Girl Friday? "Ironic. Journalists are people I have a very healthy disrespect for," she says with a throaty chuckle.

Wanamaker, who is married to the actor Gawn Grainger ("an extraordinary person", she tells me with the huge, self-satisfied grin of the utterly in love), has performing in her blood. She was born in America to an actress mother, Charlotte, and actor-director father, Sam. The family fled to Britain to escape the McCarthy trials in 1952. Her parents were keen to dissuade her from entering the family business, not because they didn't believe in her talent but because "they didn't think I'd have the guts for it". So she bided her time. She would have liked to write, but suffers from mild dyslexia. "I tried to be a secretary once, and it was a disaster," she laughs. "And I went to art school, but I somehow couldn't find my way into it. I think I knew really that I wanted to be an actor. I was just tap-dancing until my parents calmed down about it." Even at drama school, she didn't immediately find her feet. "I didn't have much confidence. I spent most of my time hiding at the back of the class. It's taken me a long time to get past that, and it still happens sometimes - every day is a minefield."

Why should an actor of Wanamaker's consummate and acclaimed skills harbour such insecurities? A down-to-earth nature is probably partly responsible for her appealing lack of hubris, but perhaps her family's early experiences in this country, which she says had an enormous impact on her, are also a factor. "We were immigrants, not only American but Jewish. We weren't part of the British elite, we weren't part of society, and we were treated like aliens. I always felt different."

Tellingly, it was the Jewish-American Sam Wanamaker, rather than an indigenous Brit, who fought for the rebuilding of Shakespeare's Globe Theatre. Recently he was honoured with a Blue Plaque in Southwark - but it was decades before his plan was taken seriously. Wanamaker's face glows when she talks about her much-missed father, who died from prostate cancer in 1993. So drawn-out and agonising were his final days that she considered helping him to die; she is now honorary vice-president of the Voluntary Euthanasia Society. The fact that the Globe stands as testimony to his dream is, she says, "bloody nice. I feel he's been exonerated, I feel he's been proved right. His incredible tenacity and belief has paid off in bundles. He was rejected so often and so virulently in his fight to build the Globe, and his vision was derided and laughed at."

But if it has taken a long time for Britain to embrace the Wanamakers, we're making up for it now. The BBC, the National Theatre - Wanamaker is currently right at the heart of the artistic establishment. In 2001, she was even appointed CBE. What did she make of that? "Well," she purrs, flinging a well-turned leg over the corner of the table and leaning back in her chair, with a smile of quiet, deep satisfaction, "that was a shock. No, I thought of it as being for Dad. I couldn't think that I'd possibly done anything to deserve it. So it was fantastic." In its combination of mischief and modesty, that response is typical Zoë Wanamaker. But she can make light of her achievements all she wants; whether she likes it or not, she is well on her way to becoming a national treasure.

'His Girl Friday', part of the Travelex £10 season, is at the National Theatre, Olivier, London SE1 (020-7452 3000)