On the first day at her US university - chosen over Cambridge because the latter was 'a bit Hogwarts-looking' - Emma Watson was bombarded by autograph hunters.
She was caught so unawares that she couldn't contain her shock: 'Everyone looked at me horrified, like, "Oh my God, what's wrong with her?"'
You can understand why she was so devastated. Her presence at Brown University, the Ivy League establishment in Providence, Rhode Island, had been meticulously planned.
Emma, 20 - the highest paid actress in Hollywood last year, thanks to her role as Hermione Granger in the Harry Potter films - had already raised eyebrows when she declared that, instead of throwing herself full-time into the movie world, she would return to her studies.
Symbolic gesture: Emma Watson reveals how her short new haircut marked the beginning of a new phase of her life
So how did she deal with the unwanted autograph hunters, once she had overcome her initial shock? In typical Emma Watson (and Hermione) style, it appears - with quiet determination.
She dusted herself down and decided that she would proceed as planned, on her terms. 'I just said, "I'm really sorry, but I'm here to study and I just want to be a student. Would it be OK if I don't sign, because you'll be seeing me around all the time anyway?"'
The fact that she has now completed her first year of studies is clearly something of a triumph, not least, she admits, because not a single shot of her in the shared uni bathroom has made its way onto the internet.
'One morning I was walking down the corridor from the bathroom in just a towel and I thought I must be mad, anyone could just snap me,' she says, laughing. 'But no one did. Not even when I had my birthday party. 100 people came, and not one person put a picture on Facebook.'
It's perhaps not as astonishing as some think that she opted to continue her studies rather than hurl herself into a celebrity lifestyle.
Emma, who got the part of Hermione when she was just nine (she recalls being propped up with cushions at her first press conference, so she could reach the mike), was always the 'thinker' of the Harry Potter child actors.
Beginning of the end: Emma as Hermione in Harry Potter and the Deathly Hallows - Part 1, with co-stars Daniel Radcliffe and Rupert Grint
She was also the least likely of the trio to go off the rails. Proud of her goody-two- shoes image, she once admitted 'there's no point getting drunk when you've got ten hours on set the next day'.
Does she ever go wild now? 'It's not worth it,' she says. 'You can imagine the fallout.'
She's not quite as earnest as she once was, though. She admits, with glee, that she has recently acquired a trashy taste in TV - possibly as a reaction to daytime academia.
'What I've been watching most of recently has been Sex And The City. If I'm honest, that's all I can really take in. I need something that isn't going to be too demanding. So it's romantic comedies, Sex And The City and Gossip Girl.'
With part one of the seventh Harry Potter film, The Deathly Hallows, just released, it seems that Emma is rather enjoying life outside the Potter bubble, despite her tears when filming finished (although part two is not released until next year, it is all in the can).
Goody-two- shoes image: Emma was always the least likely of the Harry Potter stars to go off the rails
In an interview to promote the film she talks warmly and affectionately about her time in the bosom of 'the Harry Potter family'.
She giggles away about the things she struggled to learn on set. Hilariously, having to master riding a broomstick seems to have caused her more grief than attaining straight As in her exams.
'I'd never done it before this movie, and it's so uncomfortable. I have no idea how Dan did it. I was in awe. It is the most painful uncomfortable experience I've ever had.'
But there is a distance there too, as she admits that life away from the world of movies has been an eye-opener.
'Sometimes when you are in it, it is all just a blur. Now, with some distance, I feel like I can have perspective on it. I feel more grounded.'
Physically, of course, she is no longer Hermione. Just after she finished filming, she walked into a hairdresser in the States, handed him a picture of Mia Farrow and asked him to cut off her 'Hermione' hair. When her dad found out, he wasn't exactly thrilled.
'When I first told him that I was thinking about doing it, he said: "Don't get carried away. You're not Audrey Hepburn yet." But he loves it now, and so he's eating his words.'
She agrees that the haircut was a symbolic gesture. 'I'm 20 now, so I'm not a child any more. I've been on Harry Potter for ten years now, so I felt the need to mark the end of it in some way - I needed some way to say to myself, "Right, you're entering a new phase of your life now." I needed a change, and that's what the haircut is about.'
The miracle, of course, is that Emma can be anything approaching grounded, and her account of the whole incredible journey - from school to becoming the face of Burberry - is told with a palpable sense of disbelief.
She says that one of her most vivid memories of the whole Harry Potter phenomenon was a screening in New York, to which 5,000 people turned up.
'I've been on Harry Potter for ten years now, so I felt the need to mark the end of it in some way... I needed a change, and that's what the haircut is about''I remember walking onto the stage and seeing just people with flashes. I think that was the moment for me where I realised the scale of what we had achieved, and how big it all was.'
So what has been the key to remaining grounded? She credits her parents, both lawyers - who divorced when she was five - for laying down the law. It was they who insisted that she continue going to school when possible, and famously allowed her only £50 a month pocket money when she was earning millions.
'I think the fact that I kept going to school really helped, because I have a life and friends outside the film industry, which is a bit nuts. And I guess it's partly my upbringing, my parents. We haven't made these films in Hollywood; we've made them in Watford, and we've really been in our own bubble, so we've had quite a normal existence in a way.'
There's no doubt that her bank balance means a 'normal existence' is tricky to maintain.
'I hope it doesn't complicate relationships for me,' she admits. 'I think it can make guys quite uncomfortable. I do have to be sensitive. I'm a student right now, so I'm not going to trot around college with a £1,000 handbag. That's silly.'
She remains close to both Rupert and Daniel, and seems bemused by how they have both developed.
'It's funny, they've both gone completely opposite ways. At the beginning Rupert was very confident, really chatty, very outgoing, and Dan was the quiet shy one.
Fashionista: Emma pictured in London earlier this month (left and centre) and in New York (right) promoting Harry Potter and the Deathly Hallows - Part 1'I remember at the first press conference, he was so overwhelmed by the whole thing. Now, you can't shut Dan up. He's telling jokes, he's got this incredible energy. Rupert's gone quiet. He's much more reserved.
'We are like siblings. If I'm feeling a bit anxious or I need to talk something over with someone, Dan's the one I'll go to. We had this great weekend once. We were stuck in the middle of nowhere in Scotland in this castle.
'We were both meant to be in bed and I sneaked into Dan's room and stayed up watching movies all night, drinking Coke and eating M&Ms from the minibar.
'Rupert's the guy I go to when I want to be relaxed and have a good laugh. His dressing room is like a child's wonderland with every kind of game, every kind of sweet, every kind of whatever you can imagine. I go to him if I want to snuggle up on the sofa and watch television.'
But it is from the 'grown-up actors on the Harry Potter set that she feels she has learned most. She cites Helena Bonham Carter and Emma Thompson as her role models.
'At the beginning Rupert was very confident, really chatty, very outgoing, and Dan was the quiet shy one. Now, you can't shut Dan up. He's got this incredible energy. Rupert's much more reserved''I learned from Emma how to behave on a set. She remembers everyone's name, she's incredibly courteous and considerate, and she makes everyone laugh.
'It's up to the leading actors and actresses to set the tone on a film set, and the first time I saw Emma I remember thinking, "That's the kind of actress I want to be."'
Indeed, when filming finished, Emma Watson bought all the crew members a Smythson leather notebook engraved with her thanks and a quote from Dickens: 'The pain of parting is nothing to the joy of meeting again.' Emma Thompson would surely have approved.
The family atmosphere on set wasn't always helpful, though, and she confesses that a much-talked-about love scene with Dan in the latest film caused some terror.
'I was a bit nervous. I think that David [Yates, the director] didn't want us to get too nervous so he only told us a day before we were going to do it, which helped. But at the same time I felt a bit panicked.'
She blushes when reminded of Dan's mischievous comments to reporters that she is a 'fiery' kisser. 'He called me an animal, I read; I guess I should take it as a compliment.'
What's striking is that she seems to take the media hoopla in her stride. 'It's experience,' she explains. 'I'm 20 now, and I was nine or ten when I went into my first press conference. So you just get used to it. It takes too much emotional energy to get upset every time something is written that you don't want to see. You just have to let it go. I would be a crazy person. Maybe I am a crazy person.'
Or maybe not. With her, everything is meticulously planned. While studies are the focus of Emma's life at the moment, there is no question of writing her out of the Hollywood scene. She is continuing to act, and is currently working on My Week With Marilyn, in which she plays a wardrobe assistant to Marilyn Monroe.
Friendships for life: Emma as a teenager in 2005 with Rupert Grint and Daniel Radcliffe in Harry Potter and the Goblet of Fire
'You have to be really organised with your time. I tell professors in advance that I have to leave for this period of time, and I hope they'll understand.'
Where does she see her professional life going from here? 'I guess I just want to keep making films that are on the same level and quality of Harry Potter - but not necessarily with the same budgets, or fan base.'
Juggling university life with a top-level acting career seems like a tall order, but Emma says she's a consummate juggler. When her mum and dad split up she was 'juggling two parents', and when Harry Potter came along there were two different lives, work and school.
At one point, as A-levels approached, the pressure got to her. 'I felt I'd been ripped into a million pieces. I had a freak-out. But then I took a deep breath and thought: "I'll make it work. I'm not prepared to give up either thing, so I'm going to work my a*** off and do them both".'
So she did. And seems determined to do so again, convinced that she can keep both worlds separate, even when they seem set on colliding.
Last year, she reveals with a laugh, her university mates threw their annual Harry Potter party, apologising to her, but pointing out that it was a uni tradition. Her reaction? She politely said she understood, then stayed well away.
Harry Potter And The Deathly Hallows: Part 1 is in cinemas now.
LOOK HOW SHE'S GROWN!
From fresh-faced schoolgirl to the face of Burberry - Emma Watson's life in pictures...
Emma at the age of nine as her journey was about to begin
As Hermione in Harry Potter and the Philosopher's Stone
With JK Rowling at the Philosopher's Stone premiere
At the Prisoner Of Azkaban premiere
On media duty for The Order of The Phoenix
With Chanel designer Karl Lagerfeld
At Brown University in America
As the face of Burberry