Never mind that she's appeared in Quentin Tarantino's Death Proof, Edgar Wright's Scott Pilgrim vs The World (as the ultra-cool Ramona Flowers) and played Bruce Willis's daughter in Die Hard 4.0, she still estimates her career has been gradual, her fame the opposite of overnight. "Even people who are actual fans of mine will meet me on the street and not know who I am, then tweet me and go 'Oh my God, I had no idea it was you!'"
If that is testament more to her love of character work than a lack of personality or presence, the forthcoming period may be a crucial one for the 28-year-old actress.
Not only is she reprising her role opposite Willis in A Good Day To Die Hard, Winstead can also be found basking in the aura of a post-meltdown Charlie Sheen in the oddball comedy A Glimpse Inside the Mind of Charles Swan III. But it's as an alcoholic trying to dry out in Smashed that is the film most likely to take Winstead to the next level.
Playing Kate, a primary school teacher who comes to realise that her boozy lifestyle with her husband (Breaking Bad's Aaron Paul) is spiralling out of control, Winstead's emotionally raw, high-wire turn is one of the most talked-about this year; already nominated for Best Actress in the Independent Spirit Awards, she looks a good bet for an Oscar nod.
Based on the experiences of co-writer Susan Burke, Winstead worked "around the clock" on her character, attending AA meetings and listening to painful tales of addiction. "That was something I was afraid of; that I didn't have a deep enough history of pain to be able to draw from," she says. Yet she changed her tune when she realised that "pain is pain", whatever degree you've felt. "It allowed me to acknowledge my own pain, and to feel it. It gave me the licence to indulge in my own problems."
What these problems are, Winstead won't reveal. Does she have addictive tendencies?
"I don't think so. I can be set in my ways, though I'm not sure that's really an addiction." Has she seen Hollywood excess? "I've seen people who are rarely, rarely sober and people who I've never seen sober and I don't even know them sober ... and that certainly makes you think: what type of lifestyle is it where you can live every day in a drunken haze and everyone is totally fine with it?"
Winstead is a distant relation to Ava Gardener, former spouse to hard-drinking Rat Pack legend Frank Sinatra. "It's my grandfather's cousin on my Dad's side," she explains. Winstead was only six when Gardner died and she never met her, though with her pale skin, brown eyes and bobbed dark hair, you can see the resemblance. "She's so gorgeous and alluring," she sighs. "I watch her work and try and see if I inherited anything – any little detail."
Born in North Carolina, and later raised in Salt Lake City, Winstead was an aspiring ballerina before she switched her to acting. The youngest of five, she began sending out demo tapes to LA agents.
She admits: "I had some tough years, when I wasn't working as much as I would want. And I had to think about whether I wanted to go to school full-time or carry on. My parents were very supportive."
She still lives in LA, with her husband of two years Riley Stearns, a writer-director with whom she's made several shorts – though they steer clear of the Hollywood bubble. "I have my group of friends but we're all separate from that." Typically, at events, she's the outsider. Can she schmooze? "I'm the worst, I'm the worst. I'm terrible. I think I'm one of those people that others think is stuck up, because I'm so incredibly shy."
She was even scared to speak to Bruce Willis during A Good Die To Die Hard. She says: "Some people are different to their screen personas, but he's so similar to that. It's intimidating."
She spent time with Charlie Sheen on A Glimpse Inside The Mind of Charles Swan III, a '70s-set comic-fantasy from Roman Coppola. She says: "He's eccentric. But most actors of his generation are."
Winstead has another film with Smashed director James Ponsoldt, teen tale The Spectacular Now. "I would be in any film that James is directing," she says, her gratitude stemming from the fact Smashed was the first film she helped initiate. "I set out to do a film like this ... and to not just let my career be dictated by what people are willing to give me. [I wanted] to go out there and make things happen for myself."
Smashed opens on December 14.