Imogen Poots - A blooming English Rose

Today, there's not a bonnet in sight, with a chic-looking Poots dressed in jeans, a black cardigan, beige flats and a matching raincoat. Still, it's not hard to see why casting directors have targeted her for period pieces. She has the English Rose look down pat: pale skin, petite features, blue eyes and curls of long blonde hair (today clamped to her head with Ray-Bans). Of course, she doesn't see herself this way, telling me that someone once said she resembled a Moomin, the white hippo-like cartoon creature created by Tove Jansson. "I do look like a Moomin, with this nose!" she giggles.

While that might be stretching the self-deprecation a little too far, she's evidently keen to avoid being shackled with the English Rose image. When she was just 17 and still at school, she became known for playing Robert Carlyle's daughter in 28 Weeks Later. But much of her work is firmly anchored in the past, whether it be Jordan Scott's boarding-school tale Cracks or Richard Linklater's Me and Orson Welles.

So there's a sense of relief in Poots's voice when we move onto her new film Chatroom, an adaptation of the play by Enda Walsh. Set in the murky world of internet chatrooms, it follows a group of five pasty-faced British teenagers (led by Kick-Ass star Aaron Johnson) as they meet online and begin to encourage antisocial behaviour in each other. While each teen is logged on at home, the film visualises the web as a physical set of rooms – all connected by a Dante-inspired corridor of hellish debauchery – in which the characters come face-to-face. Poots plays Eva, one of those whom Johnson's cocky William manipulates.

"It's so relevant to now," enthuses Poots. "It's great to be involved with something that represents my generation." Yet the problem with the film, as the critic on film and culture site The House Next Door pointed out when the film made its debut in Cannes earlier this year, is that "no teenager has used a chatroom since approximately 1997".

Even Poots seems aware of this. "I didn't go on chatrooms. Just Facebook," she says, admitting she joined the social networking site for a while. Poots calls herself "inept" when it comes to technology. She has a BlackBerry to "keep track of emails" and only seems dimly aware of Amazon's Kindle book-reader. "Why would you choose to do that instead of going to a book store and buying a novel?" she asks. "It's crazy."

If anything makes Chatroom relevant to today's social networking craze, it's how people are willing to reinvent themselves online. "It's extraordinary how people present themselves. They can say things they want and transcend their own personalities and dismiss their own identity," she says, calling the internet "intrusive" for the way it exposes individuals. "No matter what you say, you're still contributing to, 'look at me, look how cool my life is.' It's interesting to see just the photos people put up. What are they trying to achieve?"

How does she feel being in an industry that in its own way is as exposing as the internet? "I think there are ways to be discreet," she says. "I think going into the industry, you are putting yourself out there to an extent."

As the daughter of two journalists – her Belfast-born father, Trevor Poots, worked with Sir David Frost, most recently on BBC4's Frost on Satire – Poots presumably has an innate understanding of the way the media operates. But after a private West London education, which concluded at Latymer Upper School, where she gained 3 As at A-level, she never had a desire to follow into the family business. "Once I started acting, I loved it so much," she says. "It seemed crazy to just dismiss something like that."

Thankfully, Poots wasn't one of those annoying stage children who took any opportunity to perform in front of their parents. "Oh God, that's the worst thing ever," she groans. While she eventually enrolled in an impro workshop when she was 14, acting wasn't initially on her radar. "I wanted to be a vet at one point, then I fainted when a cat had its gall-bladder stones removed on my work-experience day. My mum made my packed lunch and said, 'have fun!' Then she came back to collect me and I was all limp and being dragged out of the surgery."

Even now, Poots still toys with the idea of returning to formal education. She has a place on hold at London's Courtauld Institute of Art. "They're being very sympathetic and I've deferred it for a couple of years," she says. "If you want to know about the Scrovegni Chapel, you can read a book on it. But if you really want to know about it, and everything leading up to and after those Giotto frescos, then do the degree". It's hard to see Poots finding time to take the course on.

She has already appeared in Solitary Man, in which she plays an impressionable youngster who winds up having an affair with Michael Douglas's down-on-his-luck car dealer. While the film went straight to DVD in the UK, trade-paper Variety has just cited Douglas as a Best Actor contender for the forthcoming Oscars. Creepy though it sounds, Poots even shared her first on-screen kiss with the actor (45 years her senior). "We filmed it in a penthouse in New York, and I remember looking out the window," she says, wistfully recalling the Manhattan skyline. "But I felt very calm, because he was so calm. And really caring."

She has just completed a second major Hollywood outing, snagging the lead in a remake of the 1985 comedy-horror Fright Night, in which she'll star opposite Colin Farrell. Yet all eyes will more likely be on a home-grown production, a new version of Charlotte Brontë's classic, Jane Eyre. Directed by Cary Fukunaga, who made the well-regarded US-Mexican gang-thriller Sin Nombre, it stars Michael Fassbender as Rochester and Alice in Wonderland's Mia Wasikowska as Jane. Poots plays Blanche Ingram, the avaricious socialite Rochester courts to enrage Jane with jealousy.

"Obviously, in the book she's presented as pretty conniving and is extremely hostile towards Jane," explains Poots. "But I think Cary wanted to give her a fresh image. And the way that we've explored her character is by presenting her as someone quite innocent and generally flabbergasted as to why this man doesn't want to marry her. Also Cary has made it much younger, having Michael Fassbender and Mia Wasikowska as the two leads. And it's much more sinister than any other adaptation."

Alongside Jane Eyre, Poots has already filmed Christopher and His Kind, yet another period piece – this time about author Christopher Isherwood. She features as Jean Ross, the inspiration for Sally Bowles in his novella Goodbye to Berlin (who gained screen notoriety in Cabaret). Still, having worked with Aaron Johnson on Chatroom, it's clear she has a hankering to try her hand at an action movie. "Look at something like Iron Man 2 – Scarlett Johansson is brilliant," she says. "As long as you keep evolving as an actor, that's the key." Too true: it' the only way an English rose can flower.

'Chatroom' opens on 24 December