Emily Blunt - A Brit at home in Hollywood

'It's different for everyone, but you do feel like you've got to crack the whip; get on with it before they change their mind," laughs Emily Blunt, whose latest role sees her embroiled in a lengthy engagement with no wedding ring in sight. Whilst it's a raunchy comedy, The Five-Year Engagement takes its cue from the popular wisdom that long, drawn-out engagements are less likely to result in a walk down the aisle than shorter betrothals.

"I'm possibly the wrong person to ask. I got married after a year of engagement," acknowledges Blunt, 29, who dated the US actor John Krasinski for just nine months before becoming engaged. They walked down the aisle two years ago at their friend George Clooney's home at Lake Como, Italy. Before that she was involved in a three-year relationship with the Canadian crooner Michael Bublé. Having come to the attention of Hollywood six years ago with a break-out role in The Devil Wears Prada, the British actress has effortlessly adapted to the ex-pat lifestyle and lives with her husband high up in the Hollywood Hills overlooking Sunset Strip. "It's such a lovely time for me right now," she says. This year, she has already starred in Lasse Hallstrom's Salmon Fishing in the Yemen and has roles forthcoming in the sci-fi action film Looper with Bruce Willis, and the independent comedy Your Sister's Sister.

"Happiness is different for everyone. Some people are happy cultivating drama, but I'm personally quite even and easy-going. I'm just enjoying the selfish spontaneity of life right now, which I think all changes when you have children. I'm from a big family, so I would like to have children. I don't quite know when, though." The second of four children born to actress Joanna and high-profile barrister Peter Blunt, she was raised in the affluent west-London suburb of Roehampton. "I've got plenty of time. I have a lot of friends who are having babies right now, and I feel like there are so many social opinions on it from other women. It's all so snobby and imperious the opinions that some women have on motherhood. 'You didn't breastfeed?' That is so condescending. It seems like the worst part about being pregnant is the birth classes where everyone asks, 'Is this your first?'. That's the part of it that I dread," says Blunt.

"I think those attitudes are a very American thing although there's no going back for me – this is my home now," she says. She still indulges in British treats such as tea and toast and apparently forcibly introduces non-Brits to Marmite on set.

Today, as we chat in a Beverly Hills hotel just 10 minutes from her home, she's all movie-star glamour, dressed in a cream Dolce & Gabbana silk dress which sets off her porcelain complexion and orange strappy sandals. Her brunette hair is cut in a choppy bob framing bright blue eyes.

It's those eyes that allow her to pull off an uncanny likeness of Princess Diana for a scene in The Five-Year Engagement where she poses as the late princess at a New Year's Eve fancy-dress ball.

"We did the blue eye-shadow and the lipstick first and then, once the blonde wig was on, it was quite surreal," she says, recalling how she learned of Diana's death in 1997 hours before her family. "As a kid, I was always up before anyone else, practising my cello, and so I turned on the TV and it was just everywhere, and I woke my mum and dad to tell them. It was just this ghastly moment where she started crying and my dad sort of keeled over the bed". The actress has form playing royals. She starred as Queen Victoria in The Young Victoria in 2009 and is rumoured to be playing Kate Middleton in a television movie. "No one has offered me a Kate Middleton part," she demurs. "Maybe there's just a royal overload at this point."

While The Five-Year Engagement looks at the problems involved when partners have separate dreams they wish to pursue, she doesn't believe marriage means abandoning ambitions: "Everyone needs a dream to follow, and is entitled to one. I don't think it's selfish. Ideally, your other half emboldens you to be more than you ever thought you could be. To be honest, things have only got better, and more exciting, more boundary-less, actually, since I met John."

Blunt was lucky to realise her dreams early. Discovered at 16, she made her stage debut in Paul Sellar's musical Bliss at the Edinburgh Fringe in 2000 while studying for A-levels. She went on to appear in the West End and on TV's in Foyle's War and as Catherine Howard in Henry VIII. A versatile actress, she has worked in action, drama and comedy with stand-out roles in Charlie Wilson's War opposite Tom Hanks, and in last year's sci-fi thriller The Adjustment Bureau with Matt Damon. "You've got to love this job because it definitely knocks you around at times," she says. "It's a very personal job, and so when you achieve something, it's so rewarding because you take it very personally. And then in the same stretch, when you get rejected or someone is overly critical, it does hurt. I think that you've got to kind of wear a helmet and roll with it and not place too many expectations on this business because if you invest in it too much, it's going to devour you."

Blunt has reportedly been considered for action-hero roles from The Black Widow to Catwoman to Captain America's girlfriend Peggy Carter. "I'm fatalistic," she says. "If I don't get the role, I don't tend to pine or rage about it. You have definite disappointments, but I really don't dwell on them. I'm a big believer in fate and timing, and, if the moment's right, you're going to get the job that's meant for you."

'The Five-Year Engagement' is out on 22 June; 'Your Sister's Sister' on 29 June