Shepherd’s Bush-born actress Bel Powley was the star of Sundance Film Festival for The Diary of A Teenage Girl but, as she tells Stephen Milton, there’s still a long road ahead

Bel Powley’s enjoying an impressive trajectory of late. The articulate, saucer-eyed newcomer was the toast of Sundance Film Festival earlier this year for her compelling performance in Marielle Heller’s The Diary of a Teenage Girl; based on the graphic novel by Phoebe Gloeckner. It’s a breakthrough strikingly similar to that of Carey Mulligan for An Education, who went on to land an Academy Award nomination for Best Actress.

One can think of worse footsteps to follow. Bel, born Isobel, offers a veteran’s sigh. ‘People always assume that when you’ve broken out, it’s just happened. But I’ve been doing this for 10 years. I’ve been acting since I was 13, it’s been baby steps. It wasn’t “I did a couple episodes of Benidorm and then welcome to Hollywood”,’ she says.‘I was working in London and New York in TV and on stage for years and moved into film. It actually feels like a slow, steady trajectory. It doesn’t feel “Oh my God, it’s all happening so quickly”.’ She pauses and ponders her last words. ‘Although to hear “you’re the queen of Sundance; the Sundance breakout,”’ that’s mental. It’s just, I know everything is a moment in time, you know. Right now, Sundance, all that, everything is amazing but this industry a risky business. I’ve a long way to go. And I’m prepared to graft to get there.’

The daughter of an actor father and casting director mother, the sharp-toned 23-year-old from Shepherd’s Bush is indeed no overnight sensation. Early performances on BBC series M.I. High led to steady work throughout her teens in Little Dorrit and Robbie Coltrane’s crime drama Murderland. On stage, a debut at the Royal Court at age 17 was followed by her work in Arcadia on Broadway opposite Tom Riley and West End hit Jumpy with Tamsin Greig. Finally, her transition to the big screen is causing persistent ripples. After a smirking turn as a young Princess Margaret in the quietly received A Royal Night Out, latest release The Diary of a Teenage Girl showcases Bel’s stirring ability to carry an emotionally-driven script on her petite shoulders.

The Resident: Bel stars opposite Alexander SkarsgardBel stars opposite Alexander Skarsgard

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Bel shines as the thoughtful adolescent Minnie, a girl struggling to navigate the fresh waters of intimacy with her older lover, played by a subdued Alexander Skarsgård, who also happens to be the boyfriend to her spirited mother (Kristen Wiig). Set against magnolia hues and abstract imagery, it’s a provoking journey of female sexual self-discovery, a path often neglected by Hollywood. ‘It’s so honest,’ Bel explains over a patchy phone line. ‘It’s such an honest account of what it is like to be a teenager – and of sex. Female sexuality in the years 13 to 16 is still a taboo subject, whereas boys at that age – we hear all about them wanting to get laid. But where is the story for the girls? ‘I wanted to be part of that conversation. And I found that I was so like Minnie. On the surface, I appeared confident and precocious at times but I had that inner teenage struggle. I remember the years that I really learned to love myself, accept myself for who I am, the way I looked, and I relate in a way, because it’s a tough period to go through.’

The thorny subject of a sexual relationship between a 35-year-old man and an underage minor is one that has attracted its fair share of controversy in the lead-up to the film’s release, but is handled with a practical delicacy by first- time director, Marielle Heller. The film edges away from a Lolita-esque style, which appeared to be a hugely attractive aspect for Bel. ‘It’s a testament to the writing that when I first read the script, it didn’t jump out at me. I knew it was about a girl sleeping with a 35-year-old man but it’s so much more about a girl finding out who she is. We’ve been lucky with how we wanted to present the film and how it’s being perceived.’

Educated at the Holland Park School, Bel later migrated with her sister to Peckham, where she recently purchased an apartment, although the pull of west London always proves difficult to resist. ‘I’ve actually just moved into a new flat, which I’ve only been able to spend two weeks in so far because I’ve been working a lot lately, which isn’t a complaint. I love to travel with work but home will always be London, and Shepherd’s Bush. I love getting back there for strolls in Holland Park; it’s just gorgeous around there by the Japanese garden. And strolling round the Shepherd’s Bush Market on a Saturday. It brings back nice memories; the smells and the noises. And Portobello Market – I know I’m jumping round the place – but there’s nothing better, some of those gorgeous cafés and shops along there. Love them,’ she says. ‘I will always be based in London. I love LA and I go there a lot for work. Right now, I could spend six months in LA, happily, but that’s largely down to knowing I can always come home. Because, ultimately, where else would you want to call home?’

The Resident: Marielle Heller’s film is set in 1970s San FranciscoMarielle Heller’s film is set in 1970s San Francisco

The Diary of a Teenage Girl is in cinemas from 7 August, Vertigo Releasing

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