Close-Up: Felicity Jones

Felicity Jones's idol is Vivien Leigh: "She was so beautiful and had a look of wild abandon. I re-watched A Streetcar Named Desire and there's something so nutty about her that's great."

With her delicate, heart-shaped face and glossy dark hair, Jones, 24, is no slouch at doing pure and wild herself: in the £30m big-screen Brideshead Revisited she has just shot with Emma Thompson and Ben Whishaw, she plays Cordelia Flyte, who is, in Jones's words, "very sprightly and absolutely insane".

Jones, it should be said, is quite sane in person. Before an English degree at Oxford – "I'm glad I had that student time to be flippant about life" – she grew up in Birmingham, and started acting aged 11. (You might know her best as the voice of Emma Grundy in The Archers.) More recently she has shone in Andrew Davies' Northanger Abbey and as David Morrissey's daughter in Cape Wrath.

Brideshead ought to make Hollywood sit up and take notice, but like her co-star Whishaw, Jones is committed to theatre. She was in Polly Stenham's That Face at the Royal Court last year and now Donmar artistic director Michael Grandage has cast her in a revival of Enid Bagnold's dark comedy The Chalk Garden, as a wild 16-year-old whose life changes when a governess comes to the dysfunctional home she shares with her grandmother. "Laurel hasn't been given any boundaries; she's a bit of a zoo animal. It's nice to play someone on that cusp," says Jones. "There's something disastrously unhinged about her..."

'The Chalk Garden', Donmar Warehouse, London WC2 (0870 060 6624), to 2 August. 'Brideshead Revisited' will be released in the autumn