Juliette Lewis: Born to be wild

"Oh, I was definitely wild," disputes the actress, unleashing an unsettling, direct glare. "More wild than anyone could imagine.

"The difference was, my learning lessons weren't for public consumption.

"Hardships and heartache, all that I went through isn't known about through the public and it will never be known. It's mine, it's my own trauma and pain."

Twenty years ago, the star was top of the paparazzi hit list.

Nominated for an Oscar at 18 for Scorsese's Cape Fear, she became the industry's go to sexual oddity, a combination of lazy speech pattern and hazardous allure, landing leads in What's Eating Gilbert Grape, Woody Allen's Husbands and Wives and a career-defining turn as psychotic Mallory Knox in Stone's Natural Born Killers.

She dated Brad Pitt for three years and when they broke up, spiralled into drug abuse which landed her in a controversial Narconon rehab programme – funded by the Church of Scientology of which she's now a member.

It's any wonder Lewis managed to keep her private life under wraps.

"That whole time in my life was so overwhelming.

"Right after Cape Fear and the Oscars and all that, I couldn't deal with much. I was so introverted and didn't know how to articulate and express myself. To be thrust into interviews and talk about things was probably the most difficult part. I didn't know how to articulate very much, I only knew how to express characters."

Juliette is a schizophrenic entity. Peppering our interview with a taut, forced smile, it's largely overshadowed by a look of dimpled boredom.

Nevertheless, she manages to offer a periodic purr and raucous cackle while her lack of conventional syntax and jerky sentence structure make it difficult to follow her thought process.

I find her utterly fascinating.

On the wagon since leaving rehab seventeen years ago, Lewis emerged as tainted goods and criminally limped from one mediocre screen dud to another before 'temporarily' quitting Hollywood altogether in 2003 to form noisy rock outfit, Juliette and The Licks.

Despite a string of dismissed albums, a messy, watchable stage presence provided the chance to thrash about the international festival circuit with cerulean locks and neon war paint for five years before the Hollywood Hills tempted her back.

Finally at 40, the actress has returned to the quality highs of her early career with latest film, lofty ensemble piece, August: Osage County.

An esteemed cast including (wait for it) – Julia Roberts, Ewan McGregor, Chris Cooper, Benedict Cumberbatch and Meryl Streep – portray the Weston's, a crumbling hyper-dysfunctional family who converge on their rural Oklahoman homestead to mourn the loss of household head (Sam Shepherd).

Based on Tracy Letts Pulitzer Prize winning play, Streep domineers as Violet, the cruel, cancer suffering matriarch, who manipulates and leans on her three daughters; favoured eldest, Barbara (Roberts), lost, harangued Ivy (Julianne Nicholson) and dippy youngest, Karen (a scene-stealing Lewis).

What transpires is a mesmerising dynamic that pierces at the heart of family life.

"Everyone in Hollywood was auditioning for this movie because it was the opportunity of a lifetime," she muses in a throaty burr, sometimes so loud it rattles the water glasses on our table.

"Working with Meryl and Julia and Chris Cooper and just the entire cast, you don't get these chances every day. And you don't get material like this."

Assuming the smallest of the sister roles, Juliette – casually elfinesque today in a stripped black and grey sweater and fatigued army green jacket – shines as ageing beauty queen Karen, frantically clinging to the illusion of lasting youth.

"Even though she's of a sunny disposition, this is masking a whirl of anxiety and desperation.

"It's interesting because I'd recently been through a hard time where I almost lost my father. I wasn't able to totally view life as rosy. So to get a character who only sees the positive, or will only look at the good, I loved this idea."

The cast lived in close quarters on the set outside Tulsa and came together each night on the command of Streep.

"We all had these condos that were exactly the same, though Meryl wanted us to live in a house together but they couldn't find a house big enough.

"So instead, we'd go to her place for a pot luck, where everyone brings a dish and run our lines and bond.

"And Meryl," she adds, "I know it's so cliché to gush but she commanded the set.

"She conducted the energy. It was a phenomenal experience to be in the room with her.

Growing up a child actor in Los Angeles, Lewis's own parents split when she was a toddler.

Along with older brother Lightfield and younger sister Brandy, her childhood was split between periods of living with her father, Geoffrey, an actor, and her mother, Glenis, a graphic designer – before she was 'divorced' from her folks at fourteen.

A glaring symbol of her own family destruction?

"That is so annoying that that's still out there," she sighs, rolling her eyes.

"It's what actors did if they wanted to start making money before they turn 18. Otherwise it goes straight into a trust. Over here it sounds foreign but in Hollywoodland, your parents help you do that. Well at least mine did.

"If anything, I had too much freedom. They're really non-oppressive and if anything, I have neglectful parents. They're quite pro art and bohemian, but you know, they're probably a bit neglectful."

After divorcing pro skateboarder Steve Berra in 2003 after four years of marriage, Juliette remains 'relatively' single. Her words.

"I believe in healthy love and respect. But I'm working on a lot right now, with acting and music. I believe in love in my work and that's such an important large part of me right now."

Back in the studio forging on new material with Kentuckian group, Cage the Elephant, she'll keep the balance with upcoming performances in recent Sundance select, Hellion alongside Aaron Paul and M. Night Shyamalan's shadowy new series Wayward Pines.

Working with The Sixth Sense helmer reminds the star of the power such tutelage from early collaborator's Oliver Stone, Woody Allen and Martin Scorsese had, not only on her career, but also on her life.

"I wanted to quit acting at 16.

"I was strange and not the norm. People [in Hollywood] try to make you conform and that just wasn't me. So when I got the opportunity to work with a bunch of non-conformists like those guys, and now like Shyamalan, it's enlightening.

"I look at all my directors as my teachers because I didn't go to any formal acting school.

"Scorsese was a huge part of my life in that he validated my instincts that were very raw and needed to be cultivated at that time. He told me to continue in my direction of naturalism."

Stone had so much faith in his skittish ingénue, he allowed her the freedom to compose a scene in Natural Born Killers. She radiates recalling the honour.

"The sequence in the jail cell where Scagnetti [Tom Sizemore] comes in and Mallory says, 'Do you know what I'm thinking about?' She's trying to wind him up and seduce him because she's about to punch him. And I just wrote this stuff that was sexy and sexual.

"I loved that movie. I got to be a freaking hyena, a whirling dervish, that's rare. Being female, you can play those primal energies."

Juliette enjoys looking back. Entering her fifth decade, she maintains no regrets, claiming everything that's happened in her life has contributed to the tapestry.

"I wouldn't change anything because all of it has led me to where I am today. You're wasting your time looking back when you should be living, so do I regret anything today?"

She pauses, glancing out the window and sighs. "Well I'm never looking in the past, I'm always looking forward. That's the only way I can function, I guess."

• August: Osage County is in cinemas today