WITH Sarah Bolger’s acting skills, she could pass herself off as a fairly ordinary 17-year-old. She knows what it’s like to have to be the curtain-puller in the school play.
Her dad runs the local butcher’s shop. She says she’s experienced the annoying subtle rivalries that brew in an all-girls school and, like plenty of her peers, she quite fancies Shia Laboeuf.

Then again, the reason Sarah wasn’t given the leading role in her last school play is because life for her, in truth, is a little out of the ordinary. By the age of nine, long before her friends had even been given any career advice, she had starred in her first film. Since then, she’s worked with Oscar nominee Samantha Morton in the family drama In America and played Sabina Pleasure in the film version of Anthony Horowitz’s Stormbreaker.

Right now, you can see her in The Spiderwick Chronicles, in which she plays the feisty, sword-wielding Mallory Grace.

“It’s a strong, female, dominant role,” says Sarah, explaining why she was attracted to the part. “There’s usually a damsel in distress but in this movie there isn’t. Mallory was in there, full force, wanting to protect her brothers and, well, stab Mulgarath [the ogre].”

The film is essentially a story of ordinary teenagers doing extraordinary things without the aid of any extraordinary powers.

Based on four of a series of five novelettes, it follows the travails of Mallory Grace and her younger twin brothers, Jared and Simon, as they try to protect their new house in the woods from the ogres, goblins and trolls that inhabit the sinister parallel world encircling them. Both twins are played by Freddie Highmore, the 16-year-old from London who has already co-starred with Johnny Depp. Twice.

Despite all the computer-generated imagery (CGI) and animation that have contributed to making The Spiderwick Chronicles look like a contender for the next Harry Potter-like franchise, Sarah is convinced its story would be worth telling even if all of its fantasy elements were stripped away.

Not only do the characters have to contend with Mulgarath and his army of belligerent trolls, they have their own family dramas, too, and are dealing with their parents’ recent break-up, about which Jared is particularly angry.

Mallory’s feistiness seems to stem from her determination to be a strong older sister through the hard times, something Sarah herself can easily relate to.

“My sister Emma is four years younger than me, right, and she has the same size shoe as me. You can see where I’m going with that. You have to be feisty. She’s as much trouble as twins, so I was well prepared [to play Mallory],” she says.

That said, it seems working as an actress has been good preparation for real life and, she admits, has perhaps made her grow up quite quickly.

“In this industry you have to just skip that awkward part of growing up and have to be a person that people can depend on,” she says. “Kids are going to discos, going out, people my age are drinking. I don’t do any of that, because I don’t want to do anything to jeopardise my career … I deliberately don’t do Bebo, or MyFace, MySpace, or anything like that. That’s how bad it is – I don’t even know what they’re called.” And even if Shia Laboeuf gave her a call, she’d probably not be in the country to take it. “No time for a boyfriend," she says, slamming down her glass of Coke. “But of course I want one. Who wouldn’t?”

She seems grateful, though, that her home town, Dublin, is “very grounding” and that “people don’t make a very big fuss about the film industry”.

Freddie Highmore has a similar experience when he’s back home in London. Despite being a vastly experienced young actor (he’s starred in The Golden Compass – as the voice of Lyra’s daemon, Pantalaimon – played a musical genius in August Rush, and a most convincing Charlie Bucket in Charlie And The Chocolate Factory), there’s no massive fuss made of his extra-curricular activities when he’s out and about with his friends.

“You don't really get much attention unless you go after it or are very famous. So long as you don’t stand on the street corner waving your arms around, you’re fine. Especially in London where it rains and everyone’s got their heads down avoiding the puddles,” he says.

Playing twins was "double the work but double the fun" and he jokes that, far from being paid twice for playing two roles, it was “probably more a case of buy-one-get-one-free”. “The Spiderwick Chronicles was a learning process for everyone, especially with the CGI and the twins at the same time,” he says. He was also keen to make sure Simon, the more studious and obedient twin, kept a strong place in the film, since Jared, the angry rebel, could have easily hogged the limelight.

Freddie doesn’t think he’s anything like either of those two personality types – “I don't go wrecking the kitchen when I’m angry like Jared” – nor does he have any nasty rivalries with his own 13-year-old brother, but he hopes he can be a bit more studious in the coming months as he prepares for his GCSEs. He has a personal tutor while filming, which he thinks is stranger for the tutor than for him.

“It’s kind of funny sometimes if you’ve just done an emotional scene or you’ve just been really angry on the set and then you go off to school. It’s a big change in mood and the tutor must be, like, ‘whoa, he’s changed’,” he says.

Like Sarah, with whom Freddie developed a sibling-like relationship during the four months of Spiderwick filming, he would love to keep on acting but is keeping his options open. He’ll be sitting his A-levels – probably in modern languages – as well as keeping his eyes open for any good script where his character turns out to be the murderer. “It would be great to play a really bad guy,” he says. “A really nasty person who everyone hates. It would be good, because you don’t see me as that.”

He’s right. It seems highly unlikely that he would turn out to have a nasty streak, and he laughs at the thought of turning into a troubled, fame-wrecked actor.

“The worst thing about it all is being away from family, but they are very supportive. You maybe get a bit more mature when you spend all your time around adults and they treat you as older, and there’s always that sense of it being a job even though it’s always great fun and never an obligation," he says, smiling and rolling his eyes as he adds, “but I don’t think I’ve been, like, deprived of my childhood.”

The Spiderwick Chronicles (PG) is on now at the IMAX at Glasgow Science Centre, and on general release from Friday, March 21

Meet the Creators

Illustrator Tony DiTerlizzi

So what’s it like to see your creations come to life?
It is a dream-come-true, especially as I made my first fantastic field guide to dragons and creatures when I was only 12. The goblins, sprites and Thimbletack are better than I could have imagined.

What’s your favourite part of the film?
My credit at the end! Just kidding, there are a couple of great scenes in there for me. Arthur telling Jared that since he has read the book, now he has the knowledge and he IS the book. That ‘knowledge is power’ theme was a big one for me in the books, and I was happy to see it translate into the film.

How long does one illustration take you?
The illustrations for the Field Guide took a while to do - but I was on a really tight deadline, so I worked like a dog seven days a week for 8 months. I always start with a pencil sketch on paper. I explore shapes and design, then begin the research process looking for photographic reference for the final image so there are real-world landmarks the viewer can relate to like warts, feathers. From there, I either ink the image with old dip pens or paint it in gouache.

Does Holly write then you match up an image to suit?
Holly comes from the teen novel world, and I from the picture book realm, so there was a nice meeting ground in the middle for Spiderwick. We would brainstorm the stories, she would begin writing and I would start sketching. We would share everything along the way, offering ideas to further improve the final book. Since our roles were so blurred, we left out the”written by” and “illustrated by” credits on the book.

Writer Holly Black

Has the film version passed your stringent tests?
You hear all these horror stories, so you don’t know what to expect, but I’ve been thrilled. The movie did a great job of distilling the important parts of the books: Jared’s anger issues, the organic look of the faeries and their capricious, dangerous nature, the fact the family is going through a divorce and the interpersonal relationships between the siblings.

There are some dark moments – was it always your intention to scare the reader?
When I turned in a first draft of the first book, our editor, Kevin, told me to not be afraid of letting the books have some darkness. We think of the Spiderwick books like a contemporary Grimm’s fairy tale - with all the darkness of the originals as well, we hope, as the wonder.

What is the universal appeal about creepy creatures?
Everyone can relate to the idea the world might be bigger and stranger than we think. One of the things I have been continuously surprised by is how many people have had or know of an experience with the supernatural. From the beginning, when we went to meetings about Spiderwick, things would get sidetracked because people would be telling us “here’s this weird thing that happened to me”.

The Scottish Borders are renowned for their dark mysteriousness…should we start the creature hunt there?
Absolutely! The rich faerie folklore of Scotland is one of the sources Spiderwick draws upon. I have a wonderful book of ballads and I love looking through them when I get stuck for ideas.