A far cry from the cool Dana Scully who made her famous, Gillian Anderson speaks with Michael Lallo about her new film, her transatlantic upbringing and how acting saved her.

Gillian Anderson was backstage at Wembley Stadium, waiting to address the crowd at a memorial concert for Diana, when Victoria Beckham walked past. Having noticed that Beckham's collar was up, she reached out and flattened it, thinking she was doing the fashion-conscious Posh a favour.

''And you should have seen the look she shot me,'' Anderson laughs, burying her face in her hands. ''Other than the fact I destroyed her look, I also freaked her out because I did it from behind. Now, I try not to be helpful any more, especially where fashion is concerned.''

Sitting by a top-floor window of Melbourne's plush Langham Hotel, Anderson looks vastly different from Agent Scully, the X-Files character who propelled her to stardom in the mid-1990s. Gone is the flame-red bob, replaced by long, blonde locks. And in contrast to Scully's restrained demeanour, Anderson is expressive and quick to laugh, her American accent tinged with a British lilt.

She suspects that had she stayed in the US after The X-Files ended, she might have been typecast and offered only ''special agent'' roles. Instead, she returned to her childhood home of London, where she was cast in various stage productions and a BBC adaption of Charles Dickens's Bleak House.

''It's very easy for actors in the UK to switch between TV, film and theatre,'' she says. ''You wouldn't lose any credibility at all if you did a BBC drama after a Mike Leigh film. In the States, I think it's getting easier but it has taken a long time.''

Yet her latest role is that of Pamela Thornton, head of British MI7 in the Rowan Atkinson comedy Johnny English Reborn. With a stiff upper lip, Anderson plays the ''straight man'' to Atkinson's bumbling James Bond wannabe.

''The idea of being the head of anything cracks me up because I still feel like I'm 17 years old,'' she says.

''I also felt it was a challenge to do a role that was close to what I'd done before but to make it as different as possible.''

Not surprisingly, Anderson nails her character's British accent. She also finds that her intonation and vocabulary change depending on her location: in America, for instance, she goes to the bathroom, while in England, she visits the loo. But as she explained to TV host Jay Leno, her shifting accent is unintentional and any effort to alter it only makes her self-conscious.

Cultural identity has long been an issue for Anderson. As a child, her British classmates - even though she spoke like them - branded her a Yank on account of her American parents. When she moved to Michigan with her family at the age of 11, however, she became known as ''The British Kid''.

''It was a very Republican, Amway-driven town,'' she says. ''Everyone loved the way I talked and they gave me gum and wanted to know me. And, as children do, I took advantage of that attention and started bribing them for their gum. But after a while, I felt very lonely. I think I realised those friendships were based on something that wasn't real.''

A rebellious teen, she got a mohawk hairstyle, planted a pig's eye in a teacher's desk and was arrested trying to glue shut the locks on the doors of her high school. Then she discovered acting.

''I auditioned for a play at a community theatre and was cast,'' she says. ''Even at the rehearsal, I pretty much realised I was in the place I needed to be.

''I remember being on stage and people coming up afterwards giving me positive feedback. I wanted more of that. There wasn't much else I was good at but I actually knew how to do this.''

Anderson could, however, discover her next role is on Australian TV - as an unwitting participant on Border Security.

''I did smuggle some chilli chocolate into the country,'' she whispers, leaning forward. ''I have some in my suitcase upstairs … but don't print that until I leave Australia in a couple of days. It's illegal to bring food with you and I don't want to get arrested.''

Johnny English Reborn opens nationally on September 15.