Since coming to the public’s attention in Robert Altman’s 1993 film Short Cuts, Julianne Moore has built a career on playing roles other starlets would run a mile from. Who else would have the guts to go from playing a porn star in Boogie Nights (a role which afforded her the first of four Oscar nominations) to taking over from Jodie Foster as Clarice Starling in Silence of the Lambs sequel Hannibal? ‘I just do stuff that interests me,’ she shrugs, when we meet on a beachside terrace during the Cannes film festival.

Still, Moore, 47, the daughter of a military judge and a Scottish social worker has always lived on her nerves as an actress. Her best performances are touched by a raw power that sets her apart from her contemporaries. Nothing, however, will quite prepare you for her latest, Savage Grace. Directed by Tom Kalin, whose last film was 1992’s highly praised Swoon, a retelling of the notorious Leopold and Loeb murder case, Savage Grace is another true-life tale of crime and passion that became the society scandal of its day. Spanning the period 1946–1972, Moore plays Barbara Baekeland, well-to-do heir of the Bakelite plastics fortune, whose crumbling marriage (to Stephen Dillane’s Brooks) and suffocating relationship with her son Tony (Eddie Redmayne) lead to a jaw-dropping conclusion.

‘Had it been fiction, you would think this was just sensationalism or just salacious,’ notes Moore. ‘But because it’s non-fiction, you’re really struck by how epic this tragedy is. It’s a really classic tragedy of a family destroying itself. So that to me was very interesting.’ Attached to the project for five years, Moore admits that playing a woman as conflicted as Barbara was exciting. ‘She was loving and charismatic and smart and compelling and wanted to be part of the world desperately. She was also really needy and difficult and boundary-less. She was all sorts of things.’

Moore believes that, while Barbara had a history of depression and suicide attempts, part of her problem lay in her wealthy, debauched environment.

‘In a way, this is a cautionary tale. You see these very rich people with no boundaries. They have no job, they have no purpose, they have nothing to do, they have no focus. And their focus shifts to one another. They seek this incredible stimulation, because they’re not getting any stimulation in how they’re interacting with the world. So they seek sexual stimulation and stimulation with drugs . . . all this kind of stuff that happens to these people who have too much.’

Admittedly, Moore has made a living from playing characters undergoing psychological meltdown: think her allergic housewife in Safe, the unfaithful spouse in Magnolia, or her 1950s mothers in The Hours and Far From Heaven. But if you’re looking for any demons in her personal life that drive Moore towards these roles, you’d struggle to find them.

Married for the past four years to writer-director Bart Freundlich, whom she met on 1997’s The Myth of Fingerprints, and with whom she has since made a further two films, Moore has two children with him, Caleb, 10, and Liv, 5. ‘What did Flaubert say? “Be ordinary in your life so that you can be violent and original in your work!” I believe that,’ she smiles. ‘For me, that’s how it is. I have a very, very normal life. I really do, with the exception of being very lucky and privileged. I have a nice life. I have two children, a dog, and a husband. We live in New York, the kids go to school . . . we’re fortunate that we have flexible schedules. I like that. That’s what I want.’

Indeed so wholesome is Moore, she’s even been writing for children, publishing her first book last year, Freckleface Strawberry.

Yet, if there’s any suggestion that Moore is planning a career in Disney films, you can forget it. Her next movie, Blindness, is with Brazilian director Fernando Meirelles, who made City of God. She plays the wife of a doctor (Mark Ruffalo) who is left as the only person able to see after her fellow inhabitants in a small town mysteriously lose their sight.

‘It’s hard to say what it’s about. It’s a metaphor,’ she says. ‘But it’s going to be a really beautiful movie. And he’s such a gifted filmmaker, that I’m delighted to work with him.’

Just maybe it’s Meirelles who’s the lucky one.

Savage Grace, Cineworld, Fri 22 Feb, 8.45pm & Sat 23 Feb, 1.30pm.