Sundance Breakout Star Bel Powley Plays a Lustful, Lovelorn Teen Whose Life is an Open Book in 'Diary'

It only took a few days for Sundance to unofficially anoint its Next Big Star: On Saturday, the festival premiered The Diary of a Teenage Girl, a ’70s-set Bay Area drama about Minnie, a 15-year-old aspiring cartoonist whose sexual desires threatens to upend her family. As played by 22-year-old British newcomer Bel Powley, Minnie is an emo shape-shifter, alternating between brazen and heartbroken, revved-up and regretful, horny and hollowed-out.

It’s a delicate, unpredictable performance — and a highly sexual one, thanks to the movie’s pleasure-seeking plot: Minnie, who views herself as ugly and therefore unloveable, is obsessed with losing her virginity as soon as possible. So while her mother (Kristen Wiig, continuing her sneaky streak as an indie superstar) gets sucked into San Francisco’s partying scene, Minnie pursues her mom’s sad-goofus boyfriend, Monroe (Alexander Skarsgård), for a series of physically intoxicating, initially ego-gratifying sexual encounters (interestingly, the 20-year age difference between Minnie and Monroe is barely remarked upon here, and Skarsgård's character is portrayed less as a predator, and more as a dim-witted, selfish pleasure-seeker).

When Minnie begins to confuse her desires with love, she begins an emotional nose dive that’s chronicled in the movie via diary entries and lovely on-screen animation. But the real inner strength of Diary — which was acquired at the festival by Sony Pictures Classics — comes from Powley, whose voice, body, and wide-eyed gaze connect the character to the viewer with a sometimes unsettling intimacy (that connection proves especially helpful in the film’s overlong, overly repetitive second act). It’s the kind of performance that cements Sundance's reputation as indie cinema's best new-talent terrain.

Note: This post has been updated since its original publication to include new information