Toni Collette on Muriel and The Way, Way Back

Collette as Pam opposite Steve Carell as Trent in her new film The Way, Way Back. Picture: Contributed

Long before her Oscar nomination for her role as Haley Joel Osment’s perplexed mother in The Sixth Sense, Toni Collette was giving great performances. Indeed, as a child, she managed to get several weeks’ holiday by feigning severe stomach pains so convincingly that doctors actually operated on her and took out her appendix.

“My mother had told me about her appendectomy,” Collette says. “I remember asking her how they knew what the problem was. And she told me that when the doctor pressed on the spot, it didn’t hurt. But when he released his hand, she felt the pain. I kind of wanted a day off school, so I faked it. And when the doctor released his hand, I reacted.” Collette was then rushed to hospital for an emergency operation she didn’t need. “I never owned up to it,” she says.

It’s a funny story that another kind of actor would never tire of retelling, but Collette is keen to distance herself from the 11-year-old who ended up in surgery. It would make it too easy to pigeonhole her as the kind of immersive performer who might do anything to nail a role, and Collette has always fought shy of glib character sketches. Her tart, smart choices onscreen bear this out, and she’s especially proud of playing so many unprocessed, knotty “women with kids”.

Collette has played a lot of mothers – her first parenting job was raising Osment when she was 25 – but she never delivers a cookie-cutter mother. “There’s a movie type that really misrepresents these roles these women play as mums who arrive with bags of shopping and make the dinner,” she says. “Mothers wear so many hats and have very passionate relationships with their kids, and with life. I know I’ve played a lot of them, and I want to show the complexity of trying to balance all those different aspects.”

What George Clooney is to dysfunctional matinee idols, Collette is to motherhood in its many colours: in About A Boy, she was a depressed Birkenstock-wearing earth mother whose gutsy honesty both shames and horrified Hugh Grant; in Little Miss Sunshine she was the voice of reason in a minibus full of relatives going to a beauty pageant; and in her American TV series United States Of Tara, she hit some sort of motherload, as a suburban American housewife with a multiple personality disorder – one prim, one obnoxious, one butch and one feral. Unsurprisingly, in the hot new comedy The Way, Way Back, she gives another shrewd portrait of a divorcee who uses a family beach holiday as an opportunity to force her desperately unsuitable new partner (Steve Carell) to bond with her reluctant teenage son. “The audience will find her really frustrating,” she says. “But I love that she’s completely flawed.” And also shrewd: Collette rarely plays fools, and in this film it’s clear that her character has enough awareness to appreciate that this new family will never fit, but enough desperation to try to forge the bonds anyway.

Collette has worked with Carell before, on Little Miss Sunshine, where they played sister and tormented brother. A little £6m movie, it ended up making £80m worldwide, but Collette’s chief memory is how awful their VW bus smelled. “It seems to be our karma to be stuck in swampy, heated cars with rolled up windows in the middle of the summer driving for hours on end,” she says.

The Way, Way Back may also have the whiff of a winner about it, although Collette’s script selection is still based on instinct, rather than box-office potential. Despite her mainstream hits, her real interest lies in nosing out diverse roles to exploit her talent for character transformation, sometimes leaving audiences unaware she’s the same actress they’ve seen elsewhere. Typically, she first expressed interest in The Way, Way Back years ago, when the screenplay had been gathering dust on the shelf.

Her first hit movie was another project that had already passed through many hands. When writer-director PJ Hogan offered the role of a lumpy, wedding-fixated Abba fan to rising Australian actresses, some wrote back saying they were insulted he had considered them to be suitable. Collette was 22 when she bulked up by three stone to star in Muriel’s Wedding, and while another actress might have hammed up the high camp aspect to match the film’s raucous dark comedy, the movie gains real poignancy from Collette’s subtle transformation from backwater geek to mature young woman.

No wonder that walk down the aisle still haunts her almost 20 years on. “I think people will come up to me when I’m 80 and say, ‘you’re terrible Muriel’,” she laughs. “For a while it drove me insane, but then I’m completely thankful to that movie. That particular job gave me a career that I was not expecting, and it struck a chord with people.”

Predictably, after Muriel, she was swamped with fat-girl outcast roles. Qantas had another idea – they wanted her to be face of their fins, in Muriel mode. She turned all this down – but seemed to say yes to almost everything else. By 25 she was so burnt out that at one point she shaved her head so that she wouldn’t be able to accept any more roles. It didn’t work: she was soon back in front of the camera for The Sixth Sense – “and of course, they have wigs”.

One thing she has managed to keep is a low profile. In Australia she is recognised all the time, but elsewhere, she can pass unnoticed, perhaps because she’s far more striking in person than in many of her films. Her eyes are large and bright, her skin flawless, and occasionally she flashes a toothy smile. Now 40, she dismisses the idea that roles for actresses become more limited as they get older. “I’m still getting offered really good roles,” she assures me, and has been enjoying her second tsunami of work a lot more this time round – “It’s a lot more fun.”

Normally based in Australia, she has relocated to New York until the end of the year to film a new series called Hostages, which begins next month. Collette plays a surgeon whose family is taken hostage by a maverick FBI agent (Dylan McDermott), the night before she’s supposed to operate on the president of the United States. If the leader of the free world doesn’t die on her operating table, she’s told, the family will die instead.

Collette hadn’t been seeking another TV gig after United States Of Tara was cancelled, but Hostages “was exciting to me” – although there’s a work-life balance to be maintained too. Collette married her drummer boyfriend Dave Galafassi in 2003, and they now have two children; Sage, five, and Arlo, two.

Do they view her as one of those mothers with all the hats she was talking about earlier? “Oh they think I’m a goddess: they’re still kind of in love with me,” she says, wryly. A goddess? You’re terrible, Toni.

Twitter: @SiobhanSynnot

The Way, Way Back is released on Wednesday