Making the tricky transition from child to adult star is the acting equivalent of releasing that difficult second album. The public have very much made up their minds about you.
They've created a box and they've shoved you into it, and any attempts to clamber out of it can prove disastrous, as former child actors from Shirley Temple to Lindsay Lohan know all too well.
Actress Georgie Henley is only 15, but has already starred in two films which took a total of 700 million at box offices worldwide. She has spent much of her childhood on set, and is known to millions as cherub-faced Lucy Pevensie in the successful Narnia films.
Today however, she might be best described as unrecognisable. We meet in a suite at the Dorchester in London, where she is promoting the third instalment in the series - The Chronicles of Narnia: The Voyage of the Dawn Treader - and while she may be not yet a woman, she's certainly not the girl we're used to seeing on screen.
Gone are the chubby cheeks and schoolgirl bob, but she seems also to have bypassed any teen awkwardness and proceeded straight to Confident Young Woman. Her long brown hair is teased into glamorous waves. She wears a floaty blouse, a leather mini and flats. Her fair skin is refreshingly free of fake tan, and minimal make-up allows the scattered freckles on her nose to show through.
Looking stylish beyond her years, and perfectly striking the balance between glamour and age- appropriate dressing, she is the kind of understated English rose whom you might imagine sitting on the front rows at London Fashion Week in just a couple of years. In short, she looks like she's stepped straight out of a Burberry campaign.
She laughs when I tell her how grown-up she looks. "I do like hearing that," she says. "Now every time there's a press conference, it's like 'oh look, she's in heels now...'"
Of course, just as Georgie has grown up, so has Lucy, who takes centre stage in The Voyage of the Dawn Treader. Whereas the actors who play Lucy's siblings have always been a little older than the character they're taking on, Georgie and Lucy are the same age, and have, in a sense, grown up together.
"Lucy goes through a lot in this film," she says. "I think people will be really surprised because she is quite different. She's less sweet and I think that's just due to adolescence. It happens to every teenage girl. Your demeanour changes slightly. And I was really aware of trying to make her relateable for every teenage girl. Because most of them have been through what she's going through, kind of insecurities and not feeling so great about yourself. Growing together, it's made me get to know her more because she changes as I change.
"I've always been the same age as Lucy while I've been playing her and I think that makes a difference, especially being a girl, because your mindset changes quite a bit as you grow."
Generations of children have been enchanted by the land of Narnia, and have rummaged at the backs of their wardrobes, hoping to uncover a secret portal to this magic world, as Lucy did. Not only did Georgie get to grow up with Lucy, but she got to discover Narnia with her for the first time, a moment many children have surely fantasised about.
"The director of the first film, Andrew Adamson, was very focused on preserving real emotion, on seeing things for the first time, and having, like, a real sense of wonder," she says. "So he didn't actually show me the set of Narnia where the lamppost is until we shot it. I was blindfolded and guided into my place, and he told me to just walk around, that the camera would follow me. And so I turned around and I saw it for the first time." Her eyes widen in wonder, just as they do in the scene she's describing. "It was in a studio but it was ri-dic-ul-ous-ly real. I couldn't get my head around it. And so what you see is my real reaction to everything. It was incredible."
As a young child, Henley didn't harbour any particularly strong ambitions to act, and her parents certainly didn't choose that particular path for her. Growing up in the small village of Ilkley in West Yorkshire, she had a normal, quiet upbringing, and her only forays into acting were local plays and school productions. She was just seven when she first auditioned for the role of Lucy, the youngest of the four Pevensie siblings, and the first to discover Narnia. Henley's elder colleagues have most of the action in the first two movies but in The Voyage of the Dawn Treader, her character is very much in the spotlight, leading the cast in what will be Henley's last appearance in the Narnia films.
Unlike many other child stars, she has the air of a fairly normal schoolgirl. After our interview, she tells me, she's got her French homework to tackle.
She talks fondly of her school chums and a little less fondly of double maths. She is embarrassed at how easily she gets starstruck. Henley speaks with an eloquence beyond her years, but peppers her sentences with teenage words, from "humongous" to the ubiquitous "like". She interrupts me at one point to tell me I have "lovely teeth", and is refreshingly excited about the prospect of getting to borrow beautiful clothes to wear to premiers.
Still, Henley is undoubtedly more adult than the average 15-year-old. She is warm and engaging and very much holds her own in an adult conversation. But she's not yet jaded enough to hold back or edit her answers.
Does she feel more mature than her friends? "I feel like I have a certain level of maturity in different areas to my friends," she says, her hands crossed carefully in her lap. "I've spent a lot of time with adults around me. I was the youngest person in the vicinity for six months at a time. You don't realise it until you look back on it, but it was weird.
"And then you go back home and you're surrounded by a primary school of children. It's quite strange. I feel like I can talk to people quite well and I'm quite polite. When you're the youngest on a film set you do get babied a little bit. So my friends, some of them might want to go out and drink or experiment. I don't want that because I've been babied."
Regularly switching from school to the very adult environment of a film set has been a challenge. She went to secondary school for just one term before leaving to film the second Narnia film over a period of six months. "That was difficult for me," she says. "I had to make as many friends as possible and I only had about 12 weeks with them. That was hard but I came back. It took me a while to fit in but I'm fine and I have a great set of friends."
Henley gives the impression that she might be a bit of a linchpin among a gaggle of girls. She describes herself as "a shoulder to cry on" among her group and says she enjoys taking on the "mummy role".
There's something of the young Emma Watson about her, in her natural beauty, intelligence and determination not to get sucked into the fame vortex. Another child star who has cleaned up at the box office, Watson appears on the cover of this month's Vogue looking very grown-up indeed, and, as the last instalment of Harry Potter nears, looks to be making the transition from child to adult star fairly smoothly. Like Watson, Henley has been kept on a short leash by her parents, who have done what they can to protect her from the uglier side of celebrity.
Throughout filming, Henley gets three hours of tutoring each day on set.
Her mother chaperones her, and is with her today, but sits outside the room while we talk. Since promoting the second film in 2008 Henley has been given the freedom to talk to journalists unsupervised. However, she's noticed that the questions these days often take a much more personal line.
"It's very difficult when you get older with publicity because people want to find out more about you as a person and it's more important about the way you dress, if you're interested in fashion," she says.
"I've noticed that three years on from being 12, people want to know more about your personal life, especially as a girl. People want to know about your faith, they want to know about boys. It's fine to an extent, as long as they're not probing."
Boys and fashion are all very well, but the real question now is, what's next for her? She has spent more than half her young life playing a much-loved character from a series of timeless children's books, adapted for a massively successful run of children's films. Can she find work as a young adult? And does she worry about the stigma of having been a child star? "I do worry about that but I don't really fit the stereotype," she says. "People expect you to, but I don't think I do. I've had quite a normal childhood. I hear of people who act and they've never been to a real school. I think, well, good for you, you're so successful that you don't have to go to school but you're not really preparing yourself for the real world, and acting isn't the real world. I love being at school, I love being with my friends."
Has her experience so far put her off for life, or inspired her to pursue a career in front of the camera?
"Now that I've had a taste of it, now that I know what I can achieve if I really work hard and if I have a lot of luck on my side, then yes, I definitely want to act some more," she says.
"And of course, it's one thing saying you want to act, but you've got to think of back-up options. I'd love to teach. I'm also creative so anything musical would be great as well, and I'd love to experiment with writing. But acting is definitely the thing. I'd love to do something that's the polar opposite of Narnia for my next project because I'd just love to experience something new. So maybe something really modern, smaller.
"I'd like to do something more gritty and maybe let people know I'm not eight years old any more. I don't want to be pretending that I'm an adult because I'm not, but I certainly want to let people know I'm a teenager."
Fame is something Henley is only just getting used to, and she's not quite sure how she feels about it yet. Where other child stars might have the future all mapped out, this one is, for now, enjoying not knowing what's coming next.
"Some of my friends have known what they want to do for their whole lives," she says, with a shrug that suggests she just can't relate to that.
"People have said that I should try to plan the next five years or the next ten years because it will give me some kind of stability. But you know," she says, pausing to smile, "whatever."
The Chronicles of Narnia: The Voyage of the Dawn Treader is released on Thursday 9 December.
This article was first published in The Scotsman, 13 November, 2010