There is a little girl who comes from nowhere, dreams of landing the role in the film of her favourite book and it actually happens. Effortlessly, she ascends the ladder of fame and fortune. She has a fairy-dust-coated magical childhood filled with red carpets and movie stardom. There are no photos of her stumbling out of nightclubs drunk, no poisonous ex-boyfriends selling their stories; there is nothing lurid or shady or dark. She grows up. Her life changes forever. She discovers she can’t ride the bus any more but she can design her own collection of clothes, secure lucrative modelling contracts and have Capital Fun. She turns out to be beautiful, wealthy, powerful and in control. Despite her colossal fame, she remains grounded and beloved by all. She has, obviously, the perfect life. So why is Emma Watson crying into her scrambled eggs? “This book,” she says, shaking her head with disgust, “is total fiction.”

We are seated on a velvet brown banquette at a corner table in a grand hotel in New York. Breakfast sits untouched as she stares at her fact on the cover of ‘Emma Watson: the Biography’. She is dressed in a baggy jumper with her hair pulled back; her younger-looking expressive face currently registers anguish.

Previous interviews with Watson have portrayed her as a self-possessed, mature young woman who acknowledges her luck and gratitude in abundance. Perhaps, as she will later say, if I’d met her on a different morning, that side of her would have been present. But there is another side. Someone who remains, despite her best efforts, emotionally overwhelmed by the vibrations of fame.

We had just begun to talk about the hazards of being a private person in a public world when, as a gesture to underline the absurdity of it all, I pulled out of my bag a copy of the unauthorised biography – a book that chronicles how it feels to be Watson, despite the fact she never met the author.

It hit a nerve. She has it in her to laugh it off, but this morning it has elicited a raw and unfiltered response. Tears fill her brown eyes, which remain unblinking and fixated on the cover image of herself. It stares back. She can’t look away as she tries to make sense of it.

“I read these pages and it has nothing to do with my real life, who I am. It is a piece of fiction, but that’s my face on the cover.”

She is holding the book with both hands and turns suddenly defiant. “The first time I saw this book was when I was on the set in New Orleans,” she states. “For ‘The End of the World’ – a movie I just did. This super-cute 11- or 12-year-old girl came up to me and she had pages folded down and she had her special bookmark in it. It looked like she’d been carrying it around for a while. And she really wanted me to sign it. It’s really weird that it’s not just Hermione who has become someone important to people who love those books, but the idea of who Emma Watson is too.”

That she refers to herself in the third person shows how removed she is from her public persona. Indeed, she says it feels like she has three selves: Fictional Emma, Real Emma, and then the person she happens to be playing at the time. Since the age of nine, that person has been Hermione Granger.

Watson has been a famous person for 13 of her 22 years. Her tearful manner reveals she is not hardened to the realities of it.

“I started of at the beginning of the ['Harry Potter'] series adamantly protecting my own sense of self and my identity as Emma,” she says. The book has now been placed, cover down, in the space between us. “I was this nine-year-old who would be sat in these interviews going, ‘No, I’m not anything like her, I’m different because of this and this and this’ – at nine.” She sighs. “People would say, ‘You are really Hermione, aren’t you?’ and it went on and on till it got to a point where I said, fine. It’s easier for me to say we’re one person because that keeps everyone happy. I’ll go with that.” The parallels were convenient to draw.

Hermione and Watson were both hard-working, cerebral, academically driven students who aim high, get straight As, and are eager to please. But what separates Watson is that she’s an emotional person. She has unresolved and conflicted feelings that surface occasionally, as they have on this September morning.

“Today is the first day of the craziness,” she says, referring to the two weeks of nonstop publicity she has ahead, promoting her latest film, ‘The Perks of Being a Wallflower’. “I walk out of my apartment and there are paparazzi that. I’m flying to L.A. and then Toronto and then New York and back to London – it makes me emotional because it’s intense.”

Does she have the constitution to be a big movie star? “I’ve thought about that a lot,” she says. “And no, I don’t have the constitution to be a big movie star. Or a big celebrity.” She pauses. “But I do have the constitution to be a good actress. Some of the stuff is really hard for me. But I really like my job when I’m doing my job. It’s just there’s this weird blue that’s happening between being a celebrity and being an actress.”

It’s unusual for a child to grow up playing a single fictional character. Not to mention a character that makes them arguably the world’s most famous English schoolgirl. Watson wasn’t brought up in a show business family – her parents are lawyers – and she wasn’t prepared for the tsunami of attention that overtook her life.

“I was nine – I did school plays – but I had no idea what I wanted to do,” she says, still sounding in shock with how it played out. To go from obscurity to being one of the most famous girls on the planet, earning millions of dollars – an entire childhood spent oscillating between film set and a classroom – an identity crisis was inevitable.

“That’s why I’m crying. I don’t know how to juggle this leap: from a safe character I played, and a safe persona I had, to promoting this new character in ‘Perks’.”

Coming out of the bubble of the Potter films – eight in total – all she knew was that she wanted to do something contemporary next. “I didn’t want to jump into a Jane Austen role. I knew I could get fastened into a corset and never get out again,” she laughs.

‘The Perks of Being a Wallflower’ is a coming-of-age story, based on the popular epistolary novel of the same name by Stephen Chbosky. It’s set in a typical American high school in Pittsburgh, and Watson plays the rebellious character Sam, who is extroverted, complicated and damaged. She is very good at sustaining an American accent and believable as an uninhibited teenager.

Is she scared of the rejection – that people might not accept her as someone other than Hermione? “No, I don’t care if they do. For once, I really don’t. Making this film was one of the most important things I feel I’ve done. I’m proud of it. If people want to say whatever they want to say – I’m okay with it because for once, I don’t need that validation.”

Since the Potter franchise ended, she’s made a decision not to continue at the level of fame and attention that those films brought, choosing roles in quality independent films. She had a small part in ‘My Week with Marilyn’ and, aside from ‘Perks’, she’s shot ‘The End of the World’, with Seth Rogen in New Orleans, and ‘The Bling Ring’, directed by Sofia Coppola.

She’s hoping that with these new roles will come a different, more manageable type of success. “As a child, I didn’t get to make many choices in all of this. What I need to keep reminding myself is that, going ahead, I do have options. It was a revelation to me the other days, saying, ‘No, I’m sorry, I don’t want to talk about that,’ and feeling like it was my right to decide if I wanted to speak about something. Of course I did the English thing and apologised profusely, but I did have ownership of my own life.”

So, the other life. The real life. What’s that like? “It’s funny because what I’ve been trying to say is, I want people to know less. But then I also want to draw them together a little bit too.”

This dilemma played out when she first went to Brown University. Watson wanted to immerse herself in student life and chose Brown because, aside from being academically rigorous, it provided a full Ivy League collegiate experience entirely on campus in Rhode Island.

Was she worried at all about getting in?

“Not to sound arrogant, but I killed myself with those grades,” she says. “I left as little room as possible for anyone to say I got in on anything other than merit.”

Once she got there, however, her professional life impinged on her studies. She was still filming parts of ‘Harry Potter’ during her first year, and there were other obligations.

“I was doing reshoots. I was going voice recording. And I had two movies left to promote. It’s part of my job to show up. I would go from doing the ‘Harry Potter’ press tour and the red carpets to then being in class the next day. I felt like I was schizophrenic, living two completely different parallel lives. And that messes with you. I wanted to start fresh – but you can’t – I can’t divorce the side of me that is an actress and a public person, right? I have to accept that all the sides of me are part of me and I have to find a way to bring them together a bit. I tried to keep them separate but it’s too much of a head-f***.”

It’s heartening to hear her reveal a thoughtful and healthy contemplation about all this, and just as I’m about to mention it, she has second thoughts.

“I should have rescheduled this interview, because I think I’m giving you a sense of somone who is a victim.”

I reassure her that this is not the case. Watson has a friendship with J.K. Rowling, who also experienced the massive explosion of worldwide attention, albeit as an adult. They have discussed the trajectory, and it’s been a source of comfort.

“She’s someone I’ve talked to about this. There’s no way you can really advise. Just knowing that I’m not alone – there are other people experiencing it …”

And then there’s the money. Her personal wealth has been estimated at £26 million, and when the subject is raised, she bristles. She moves away from the table and leans against the banquette so that her back us up against the wall – literally.

“People are convinced that that’s the most interesting thing about me, and it’s going to take time to convince them otherwise – but I’m going to try.”

She looks exasperated. “I was interviewed at 13 or 14, and the journalist said, ‘So that means you’d never have to work for money?’ and I said yes. The quote was, ‘I never have to work for money again,’ and that quote has haunted me. People took it to mean that I wasn’t grateful, or aware of how fortunate I am. If I say it’s something that has affected my life very little, or that it doesn’t mean a lot to me, it seems I’m not appreciative.”

She shakes her head when I asked if she has any indulgences. “I don’t have a need for a lot of money right now. I’m still renting my house. I’m travelling for film work: the studios usually put me up. I still stay at my parents’ house. I have my one car – I didn’t buy an expensive car because I’m a terrible driver. I’d trash it. So I pay for my phone and my laptop, and I bought a record player – I like records – nice little things like that, but I don’t even feel like it [money] is there. It’s not that I take it for granted. It’s just that it doesn’t … I’m sure when the time comes, when I want to start a family and I want to buy a house and I want to send my kids to school it’s going to be incredibly meaningful to me then.”

There are a multitude of invasive and shallow things that go along with being a star of her magnitude. Like the global speculation generated by her chopping off her hair.

“I could not have anticipated the level of attention and scrutiny that haircut got. ‘Why did she do it? what was the motivation behind it?’ That is news to people? My mum has short hair. I’ve always wanted to cut my hair short. It wasn’t calculated to make a splash.”

She laughs at how people think she’s shrewder than she is.

“People said that was a really smart career move – it’s like, I just really liked it. I wanted to look like Mia Farrow. It was just a haircut.”

Every now and then, Watson says, she brings a friend with her to experience what she’s going through. It’s almost as if she needs a witness. “I had a friend from England come with me to one of the award shows. She did the red carpet with me and we got inside and her hands were shaking. The adrenaline – it’s a lot. Having a friend there is a nice reminder that it is abnormal. It’s a totally weird thing to do.”

Watson admits that she has got into the habit of doing things to make other people happy and it’s something she’s working to let go of. She says she gave Warner Bros. hell about getting time off to do her A-levels. “So I didn’t completely lie down – I did stand up for myself.” She smiles.

She spent a year studying at Oxford and will take the first half of next year off from work to complete her degree at Brown. She has one semester left. She might try to take some of the classes in New York – art lessons are among the options – and she is renting an apartment in the options – and she is renting an apartment in the city while shooting the movie she’s currently working on: Darren Aronofsky’s ‘Noah’, with Russell Crowe and Anthony Hopkins.

Her schedule is full. At the end of next year she’ll begin ‘Beauty and the Beast’ and she’s talking with the director, Guillermo del Toro, about whom he will cast as the Beast. The project came about when she was sent the script, and she chose del Toro as the director, a mark of her power, stature and taste.

When she has had to audition for parts, it’s always gone well. She went up for the part of Ila, Noah’s adopted daughter, and her agent called afterwards to see how it went and she said: “This part belongs to me.”

“She was, like, ‘Well, that’s cocky,’ and I said, ‘No, you don’t understand, I know I’m meant to play this role.’ The same way I did with Hermione – my parents were looking at this nine-year-old girl like she’s crazy because, I don’t know why, but I really felt it was going to work out. They were trying to prepare me for the disappointment of not getting it.”

Has she ever had it not work out? Not professionally, she says. But surely there’s been disappointment? “Yeah,” she says softly. “There has.”

There is a long pause. There’s been a moment where I discovered I’m very breakable and very human.” Another pause. “When I took time off from Brown. I was done. I was so exhausted I was like a ghost walking around. I kind of realised: no, Emma, you can’t make two films back to back while doing a degree, while flying backwards and forwards and trying to promote the film at the same time, while being a daughter and a sister, everything. You can’t do it. There will be backlash. I think it was about realising …”

She wells up. “At that moment I thought I was broken and I thought i was used up and I thought I had nothing left to give. I’d given everything and I didn’t really know what was left. But there’s a part of us that is unbreakable. You always find it again.”

Where does the resilience come from?

She thinks about this and speaks slowly. “I don’t want to get into it too much, but I was brought up by a single, full-time working mother. We were ferried back and forth with my brother from London to see my dad, who also had a full-time, very demanding job. Being the eldest, I’m the eldest of seven, dealing with moving country – all of that change made me strong.”

Watson was born in Paris in 1990 and lived there until 1995 when her parents separated and returned to England. She and her younger brother, Alex, lived with their mum in Oxford and split time between their parents, visiting their father frequently in London. Following the divorce her parents met new partners, and she had three new siblings on her father’s side and two on her mother’s.

“I think my parents, funnily enough in that situation, looked to me for strength,” she says.

That’s a lot of pressure, I say. She nods. Just then, a woman approaches the table and reminds Watson that her next interview is a “pre-interview” for the Letterman show. She’s taping it this afternoon.

She’s done the show before – several times – but she still gets nervous. She woke up feeling anxious about it, “but it will be fine”, she says, confidently. “It usually does work out fine. I just have to steel myself. He asks whatever he feels like.”

For instance? “Last time I did the show, Dan Radcliffe had just come out about his alcoholism. I said, ‘Please don’t ask about that. It’s not for me to talk about.’ And, of course, because I asked them not to mention it, he made a point of mentioning it.” She smiles. Naturally, he’ll ask about her love life, which is off limits. She’s talked around it before – how she’s had a hard time dating.

She laughs. “Those quotes have been regurgitated since I was 12. Who doesn’t have a hard time dating when they’re 12?”

She’s been photographed with a fellow student from Oxford, but she won’t comment on this at all. In a recent article it was mentioned that she won’t date actors, but she points out that it’s more accurate to say that she hasn’t actively pursued people who are in her industry and who are famous.

“I’m just aware it [fame] makes it complicated. You can’t choose who you fall for, but I’ve managed to fall for people who I’ve been at university with or whatever. They can see how uncomfortable I am with it [fame], so they’re not isolated by feeling overwhelmed with it all. They can see I am too. It’s naive to think that it would be simple or easy or desirable to date someone who’s in the limelight.”

As our time winds down, I suspect she’s unaware that having shown a vulnerable side has worked to her advantage. “I know when to put the armour on and I’m usually pretty good at it. But underneath that armour, there isn’t a special jab that I’m given because I’m famous or I’ve earned a lot of money. Like every other human being, I’m trying to figure out … life.”

She slides out of the booth and I wish her luck on the Letterman show. “Thanks,” she says, waving goodbye. “I’ll need it!”

Later that night, I watch how Letterman interacts with her. There isn’t the coy flirting that goes on with some of the other actresses, but that could be her age; it would be unseemly. Also, he’s watched her grow up. She has made a dignified transition from child star to adulthood and so he is instead paternalistic in a way that reflects his respect. She holds her own. Walking the line between Fictional Emma Watson and Real Emma Watson.