Did you have a difficult journey?" says Clare Higgins. For a moment, I see a flicker of Hecuba in her clear, blue eyes, a tiny taste of the spine-chilling froideur that has, over the years, had her winning plaudits for her performances in Greek tragedy. Moments later, when we have established that I am on the dot (have, in fact, been waiting in the cold outside) and that she has been given a time 15 minutes earlier than me and that her day will still be incredibly long, but that the earlier-than-necessary start was not, in fact, my fault, the ice melts, the eyes are sparkling and she is winsome and giggling, like the Kitty she played in a BBC Pride and Prejudice nearly 30 years ago, the one from which she still has Darcy's prosthetic nose, and the one that's still my favourite.
In these few moments, I've had a masterclass from one of the finest actresses at work today, one, according to the Telegraph's Charles Spencer, who is "the greatest British actress we have when it comes to communicating overwhelming tragic emotions on stage" and who, according to the FT's Alastair Macaulay, is "the actress who can go further", and who has won three Olivier awards (for Sweet Bird of Youth, Vincent in Brixton and Hecuba) which, she has said in interviews, she uses as dumb-bells. One thing is already clear: that this woman in jeans and cerise shirt, with a wild mane of dark hair, and a mouth that moves in an instant from hauteur to flirtation and then to quiet intensity, is utterly, extraordinarily, mesmerisingly, magnetic.
And now this actress famous for her interest in psychoanalysis (in as far as she is famous, which, amazingly, given the work she's done, and the awards she's won, and the eulogies from the critics, actually isn't nearly as much as you might think) is playing Melanie Klein, the most significant female voice in early psychoanalysis, and the central character in Nicholas Wright's play, Mrs Klein. Did she know much about her before?
"Oh, yes," says Higgins. "She was the Amelia Earhart of the analytical world. She shifted the focus of the influence of the ego from the penis right back to the breast. It is," she adds with a wicked glint in her eye, "kind of castrating for the boys. I remember reading this play 20 years ago and thinking, 'bloody hell, I wish I could play that part'. And here I am! I've always loved this play. It's funny, it's savage, it's moving and it's wise."
A passionate endorsement from Clare Higgins is, you can't help feeling, worth really quite a lot. She gives the impression, in fact, that she could only ever do work she believes in. Is that true? Higgins gives a smile that's somewhere between a grimace and a snort. "You have to earn money," she says. "Fortunately, that's always happened for me on television and film, where I don't think I've ever felt really involved." Never "felt involved"! This, after all, is a woman who's done a fair bit of telly, including Minder, Midsomer Murders, Kavanagh QC and Casanova, and a fair bit of film, including Hellraiser, House of Mirth and The Golden Compass. Most actors want to do more film. Doesn't she?
"No," she says cheerfully. "I don't want to be rich or famous." She roars with laughter, but suddenly stops. "Actually, it's true. I don't ever want to be rich or famous, because I've seen what it does to people. It just screws them up so badly. It would be lovely not to have to worry, but we do have to worry, so occasionally I have to go and do telly and things like that. But of course I don't feel involved. Acting, for me, is something you do in the dark. A bit like sex, really. You don't do it at 8.30 in the morning, in 30-second segments. You just don't."
I have a strange sense of invigoration, of myths and cobwebs being blown away. So I make an admission of my own. I haven't, I tell her, seen The Golden Compass. Higgins looks unabashed. "Nor," she says, "have I." Sorry? One of the biggest films of recent years, the nearest thing you get to Harry Potter without being Harry Potter, and she hasn't seen it? Why on Earth not? "It's not," she says airily, "my kind of book. I haven't got a copy, and I can't be bothered to get one, but I'm sure I'll see it at some point." But it took months to make and it would only take a couple of hours! "Maybe I'm a bit of a puritan," she says, "but there's something slightly obscene about watching oneself on film. Also, I think, 'Christ, I look like a sack of shit'."
But she doesn't! She so doesn't! In fact, since I've been gazing at that near-translucent skin, and those flashing eyes, I've begun to think that she is beautiful. "I haven't," she says, looking serious now, "got a pretty face, and I haven't got a beautiful face, but I think it's quite a lively face. It's a mobile face, and I'm glad about that because it means I can disappear a lot more easily." It is not, however, a face she wants to see 20ft high in the Odeon, Leicester Square which is why she didn't go to the premiere. This sounds like that near-extinct creature, an actor who thinks that fame is an unwelcome by-product of acting, and not an end in itself. Is it?
"Absolutely," she says. "I don't think I'm a very modern person. I don't think I am, really. Acting is a special activity for me. I remember doing Death of a Salesman. At a certain point in the show there'd be this strange noise that I've never really heard in the theatre before, and it was men crying." I remember. I was there. It was electric. "To me," she continues, "theatre at its best is what church ought to be, a dark place where you're allowed to have these extreme feelings together. I have been struck on quite a few occasions now by people saying, 'that changed my life'."
Higgins' own life changed when she was 14, at Stratford, at A Winter's Tale. It was Trevor Nunn's famous, all-white production, and the first Shakespeare play she'd ever seen. Judi Dench played both Perdita and Hermione. "It wasn't a person coming on," she says, "it was a force of nature. I remember bursting into tears and having a nose-bleed. And I also remember thinking, 'I wish I'd never come, because now I've got to try and do that'."
And so she did, but it wasn't easy. Struggling to be heard among five daughters of Catholic teacher parents in Leeds, she started to misbehave at school, and managed to get herself expelled. "I think," she says, as if pronouncing on some character in a script she has just read, "I was a bit of an odd child. I think I was a bit preoccupied, and a bit intense and a bit wobbly. When I was about 15, I thought: 'Bugger this, I'm going to rebel. I don't care. I want to go out in the world and do outrageous things.'"
At 17, she ran away from home, shoplifting to get by and forging a passport to get to Amsterdam. At 18, she got pregnant. At 19, she gave birth to a boy, who was adopted. A year later, numb from the pain, and feeling that she no longer had anything to lose, she applied to Lamda and got in. Shortly after graduating, she got an Equity card and an agent, and was soon working most of the time. But bubbling beneath was the pain of a loss that was growing by the day. "I knew something terrible was going to happen," she says, clutching her chest, as if the pain is still there. "I felt as if I was growing a cancer of some kind." She laughs, but the laugh is terrible. "I thought," she says, 'I'm dying'."
It was then that she found her first therapist. After a couple of years of intense psychotherapy, she began to feel better. "I thought: 'I'm safe. It's not going to happen. It's going to be alright.'" Seeing the miracles that psychotherapy wrought, she began to feel she needed to know more. She told her second therapist and, when the therapy finished, he started to train her. "He took me into groups," she says, "and mentoring some very famous people. I find it horrifying when people talk about 'celebs' as though they're gods, because I see them rolling around the floor in pain."
With the help of her third therapist she tracked down the son she hadn't seen since she was 19. She has now known him for 13 years she goes to stay with him and his fiance in Manchester and it clearly brings her great joy. But she's well aware, having mentored many people through the process, that "a lot of these reunions end in a dreadful mess". She does a lot of mentoring, and plans to practise as a therapist if acting "ever gets too undignified", or if she ever runs out of work. Which, I have to say, seems unlikely.
Psychotherapy, like acting, remains "an absolute passion". "I remember," she says, "when I first opened a book of Jung. I was a bit in awe, because I hadn't done any academic work since I was 17, and I remember putting down the book and walking about and thinking, 'I've just found out that I will never be bored again'." The two disciplines are, she believes, "completely and utterly" complementary. "I'm big," she volunteers, "on the quality of silence in the theatre, and that stems directly from my experience of silence in therapy. Some of the biggest things happen in silence. It's communicating something that can't be communicated in words."
So, the voluble Higgins loves silence. She lives in Glastonbury and is, she says, "never happier" than when she's on her own "with just the sky for company, and the earth". I've read, I tell her, that she's a druid. Is it true? Higgins gives a great peal of theatrical laughter. It is, I can't help feeling, the first false note. "I bet she says, 'are you a druid?'" she says, with the air of someone wiping away tears of mirth. Well, I say, I'm not laughing. Are you? "I always say," she says, and now she looks serious, "I'm a born-again pagan. The druids are a bit like a club, and you have to wear a lot of robes, and I'm not bothered by all that. But yeah, I'm a pagan. I feel a passionate, lively communication with the natural world."
I don't know about druids, or pagans, or the natural world, but I know a great actress when I see one, and I know a truthful performance when I see one, and I know when I meet a human being who cares about something other than herself. And Clare Higgins plays each role, quite simply, as if it were wrenched from her heart. "The best kind of acting," says this magnificent woman, "is someone who's willing to really share themselves in a generous and open way, whether that's making you laugh, making you cry, or just making you feel like you're part of the community of people around you. It should be ego-less, because what it's really about is getting this out to the audience. If someone says it's about you, you've failed."
'Mrs Klein' is at the Almeida Theatre, London N1, until 5 December (020-7359 4404; www.almeida.co.uk)