Is Emma Watson a bit of a madam? Given 10 years of international superstardom, £10m pocket money, hot and cold running Chanel, the undying hearts of a million billion children, and all by the age of 18, I imagine anyone would be. Certainly, she’s a bit aloof, a bit otherworldly, a bit most-popular-girl-in-school, when she arrives at the studio, two PRs tottering after. “We’ve met before,” I say, as she holds out her tiny princess’s hand. We only met for two seconds, of course, last year at a charity ball. She goes bright red and brushes an imaginary bit of hair from her face, clearly — and winningly — flustered.

“OhgoshhaveweI’msosorryIjust . . . I don’t remember,” she says. Sigh. Silly me! She must meet hundreds of fans every day.

Watson is tiny and pretty and delightfully brought up. There is nothing remotely suggestive or arch or sexy about her. A doll that has just been taken out of its wrapping, she is a refreshing antithesis to the ripped tights and bleached seaweed hair of the Peaches and Pixies. She wouldn’t dream of nicking clothes or getting publicly drunk or, indeed, doing anything vulgar at all. She remains like, omigod, super-embarrassed about once being linked to the Razorlight front man Johnny Borrell — “Ridiculous: I haven’t spoken to him since” — and charmingly at a loss when I ask her what is the starriest thing she has ever done.

“Um . . . I asked for a bed in my dressing room recently,” she says in her crisp, fluttery voice. Well, what about buying the ski chalet for her 18th? “That’s a family thing,” she says, smiling. “We’re all going up there for Christmas. I love skiing.” And asking all the boys at Stowe to stand up for her when she came into the room? Blank horror and incomprehension. “No. I would never. Can you ever imagine me saying that? More than anything, I just want to be treated like everyone else.”

Which is not difficult, in a way. Small and slim in a pair of jeans and a neat Cacharel V-neck, you probably couldn’t pick Watson out in a crowd. She’s just another schoolgirl, and that’s exactly the point of her. As Hermione Granger, she embodies The Ultimate Girlie Swot — a clean, shrewd, principled young lady, largely unaware of her effect on others. She’s much prettier than your average schoolgirl, of course: in profile, a veritable Sargent, all pinks and whites and Burberry eyebrows. But, she says, she’s not into that vanity rubbish. “Spending a whole day getting ready is ridiculous,” she says. She normally does her hair and make-up herself, having learnt from growing up around make-up ladies — “My surrogate mums. I hate wearing an outfit that looks too put-together and perfect. I choose the things I wear myself because I’m such an OCD control freak”.

Little by little, however, Hermione Granger is undergoing a transition. Next summer, as her sixth Harry Potter is released, she will film the seventh and eighth all in one go, perhaps because, with every passing month, Harry, Ron and Hermione are getting older and looking less like Harry, Ron and Hermione.

“I’m at a strange age,” says Watson, wrinkling her brow and asking for an orange juice, which doesn’t arrive. (She is simply too lovely to ask twice.) “I’m not a woman yet, but I’m not a girl any more. [Film companies] say, ‘Oh, in a couple of years you’ll be perfect for this.’ I’ll be like, yeah, but I want to be studying English then, so it’s going to be quite tough to choose between the two.”

Apart from Harry Potter, she has done the minor girlie fantasy Ballet Shoes and is now promoting her role as Princess Pea in the upcoming mouse cartoon The Tale of Despereaux. But what will she do when she’s too old for ribbons and mittens and magical kittens? “I’m going to have a battle on my hands, because after Harry Potter has finished, I don’t know,” she says. “I definitely want to go to university.”

And with three As this summer from her boarding school, Headington School, Oxford — “I worked incredibly hard” — the world is Watson’s oyster. She says she’s keen on the Ivy League, and she has been linked to Cambridge. I hope she goes: there’s a tenacity and honesty about her that seems wasted on the silly world of blockbusters. Witness her brilliant campaign as an eight-year-old to get the part of Hermione. “I rehearsed and rehearsed and rehearsed,” she recalls. “When I got the part, people were like, ‘Why you?’ And I just remember seeing a L’Oréal advert, and coming out with an American accent, ‘Because I’m worth it.’ That was my answer then. My answer now is . . . I don’t know, I just really got her.”

So in 20 years’ time, I can quite easily see her being a brilliant lawyer or civil servant — in a good way, of course — and perhaps she sees it too. “I have enough to hold me together without fame,” she says. “I have a really supportive family and a full life away from Harry Potter. It’s unlikely that I’ll be part of anything this big ever again, so I need to deal with that. I’m not going to take a job just because, shit, I’m not doing anything else.” She still loves acting, naturally — she would even, steady chaps, go nude. “Yes,” she says. “For Bernardo Bertolucci. It . . . depends. I’m not getting my kit off any time soon, but it is part of my job.”

Watson divides her time between her father’s house in Hampstead — her parents are divorced — and her mother’s in Oxfordshire. Rather sweetly, she is archiving all her dresses for her young twin stepsisters. “I’m hugely sentimental,” she says. “I collect and collect and collect. I have boxes full of postcards, letters and photographs.” Off-duty, she spends her time doing ordinary school-leaver stuff, such as hanging around Oxford nightclubs with her friends. “The truth is, I’m not very cool,” she shrugs. She’s not really into stepping out of line — she has never been tempted to date Daniel or Rupert, for example. “The public are desperate for it,” she rolls her eyes. “It would literally be like [a royal marriage]. Luckily, luckily . . . It would be such a nightmare.” She believes in love at first sight, but won’t be drawn on the boy she’s dating at the moment. I suspect he is a “civilian” from among her Oxford friends — she has, in the past, dated someone from a local boys’ school. Is she in love? “I don’t know,” she says, before going a bright shade of cerise.

For all her protests that she really isn’t cool, and for all the provincial nights out and boxes of keepsakes, I can’t help noticing she does love a fashion bash — the Chanel couture, the National Gallery, always deliciously attired in cream — and I definitely know someone who has styled her. So what’s really going on? “The parties are fun if you’re with friends,” she says, although meeting her public is often awkward. “I think it’s hard for people to know how to act when they meet me. Some people try incredibly hard to avoid anything to do with Harry Potter, fame or acting or whatever, and I really do appreciate it, but it can be quite awkward too. It’s hard meeting new people, for them to know quite what to do.”

So . . . is she a bit of a madam? And if not, why not? Watson giggles. “It’s really hard to say what’s jealousy and what’s people not liking me. People might just generally think I’m a bitch,” she says. Well, I don’t. I think she’s simply divine.

The Tale of Despereaux is released on December 19

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