Mila Kunis: I'm not curing cancer but I like to entertain and empower young girls

When Mila Kunis arrived in California from her native Ukraine, aged seven, with her parents (a physics-teacher mother and mechanical-engineer father), her older brother, and $250, she could not speak a word of English. “The first book I ever read in English was Return to Oz”, she recalls. “I was nine or 10, I think. It was the first time I'd read a big book, a real book.”

Two and a bit decades later, her new film, her biggest yet, is Oz the Great and Powerful (a sort of Wizard of Oz prequel, based on Frank L Baum's classic Oz book series). But she doesn't get all “it was meant to be”. Kunis isn't like that. Anyone who saw how she hilariously dealt with the lovestruck, nervous Radio 1 interviewer Chris Stark and his questions about Watford FC and Jägerbombs this week will know that. No, she's pragmatic, smart and eminently sensible.

“I loved the book,” she continues, not entirely convincingly. “I mean, I'm assuming I loved it. There were a lot of memories. I think it may have had little to do with the content and more to do with the experience.”

Kunis, 29, is big on experiences. For all its kudos and awards, 2010's Black Swan – the film which thrust her onto a drastically higher pedestal – wasn't an enormous, expensive Hollywood production. Nor was last year's unlikely hit, Ted, the most successful adult-rated comedy of all time, from the warped but brilliant mind of Family Guy creator and Oscars host, Seth MacFarlane. It's easy to imagine other actresses, still slightly ahead of Kunis on the A-list totem-pole, turning up their noses and chastising their agents: “Really? You think I want to star opposite a talking teddy bear?” Kunis laughed first, saw the film's potential second, and laughed last when the film earned half a billion dollars worldwide.

Oz the Great and Powerful probably cost more than double those two films cost put together. Sam Raimi's first high-profile outing as director since his Spider-Man trilogy wrapped in 2009 is rumoured to have a budget of $200m. But Kunis wanted to do it mostly for the chance to work with James Franco, who stars as Oz. “He's an old friend. And Sam became a great friend. For a movie this size, the most important thing was that I trusted the people.”

She didn't meet her fellow witches Michelle Williams and Rachel Weisz until they convened for the shoot in Detroit, Michigan.

“They were both hired about two months after James and I attached ourselves. They are wonderful mums, wonderful women. Just fantastic.”

She and Weisz play the evil sisters and Williams is Glinda the Good Witch, yet she insists the threesome “all bonded equally”.Her Theodora isn't all bad in any case, she insists: “She only wants to see the good in people ultimately. She has a little bit of an internal fight of good versus evil. I rooted her in as much depth, honesty and humanity as I possibly could, in a world that's so grand and bigger than life itself.”

She has learnt a great deal about a world grander and bigger than life itself of late. Though a recognisable face in the US since winning the role of Jackie on the TV comedy That '70s Show in 1998 aged 14, Kunis's public profile soared once Black Swan took critical and commercial flight. Since then she has retreated deeper into the privacy she craves. For nine years from 2002, she dated Home Alone star Macaulay Culkin yet there is barely more than a handful of pictures of the pair together. Since last year she has been dating her That '70s Show co-star Ashton Kutcher, 35. The pair reportedly moved in together last year.

Reticent on the subject of her private life, when it comes to her professional life she isn't averse to telling it like is.

“I loved the costumes on Oz,” she says, with a half-grimace, half-smirk, “... on a mannequin. Stunning. Hand-stitched, hand-designed, but on a human being, no. They are not comfortable or wire-friendly. And I did a lot of flying.” Though this is far and away her biggest-budget production, Kunis concedes that it wasn't terribly dissimilar to her other Hollywood outings, bar one aspect.

“In all films, whether you're doing a comedy or a drama, you figure it out, you play around, you trust the person you are playing opposite, and you hope it works out in the end. The flying though was something new. I've jumped out of planes. If I'd had a fear of heights, I'd have been screwed, wouldn't I? They put you 30ft in the air and say, 'see you later'. Sometimes the computer malfunctions and nothing bad happens but you might bounce up and down and if you have any sort of sensitivity in your stomach, forget it.”

Thankfully, Kunis doesn't have a sensitive stomach. In fact she's pondering a parachute-jump. her third, for fun. “Because I'm an idiot. It's frightening. I'm so stupid! There's no reason I should have done it a second time but I did, for my 27th birthday. You're attached to a person and they literally walk you off a plane. But it's great, the most amazing feeling in the world. It's the weirdest thing to explain to people. When they open the parachute, you feel your entire intestines going into a teeny, tiny ball then shooting back up and expanding. There is really something to be said for it. I really recommend it. I'm trying to get my mum to do it right now.”

Her “adventure club” comprises a tight-knit circle of “girl and guy friends” she has known since she was 10. “This was something we'd always talked about doing, and we finally followed through. I liked it because I don't like to feel nervous. I don't want to fear for my life all the time but I like doing things that I'm not comfortable with or that aren't expected.”

Anything else she's hoping to get around to? “I'm 29. A lot of things. I'll let you know when I do them.” She's a little flip suddenly, as if I'd asked something too personal. As befits your smarter than average, prettier than average movie star who's not yet 30, Kunis is already branching out. She has a production company with three female friends and a project in progress for The CW Network called Meridian Hills.

“I always wanted to produce but the right way. I'm not curing cancer here but I'd like to entertain and empower young girls. That's something so lacking. It takes place in the early Seventies and is about the young women who burned their bras.”

Kunis is also either more political than your average movie star under 30 or less afraid to speak her views publicly. Women's rights get her hot under the collar.

“The one thing I really don't understand is how many women could realistically have voted Republican for any reason in our election. I do think to each his own but this was incredibly sad and unfortunate. No, I don't even really think it's sad any more. It's just that women aren't educated to know that they should at the very least be earning the same as men. It's brilliant that the US is educating women in other countries.

“I don't think it's malicious intent on the part of American women, I think it's just that we are not educating women in our own country.”

'Oz the Great and Powerful' is out now

This article appears in tomorrow's print edition of Radar magazine