Anna Friel is coming undone. Running late for a fitting at Angels Costumiers, she flies around her kitchen frantically throwing snacks into a carrier bag while tapping at her iPhone. She’s wearing pale blue Ksubi jeans and a pair of hobnail boots, and her floppy Chloé blouse gapes open at the back. I have to restrain myself from reaching over to zip her up — she’s obviously mortified that I’ve caught her in such a flap as it is. Her life has been one big juggle recently, what with her recent move back from LA, multiple film, theatre and television projects in the offing, and a boyfriend, a kid and two cats to look after. Finally she sits down and breathes. “Right now it is, yes. But I don’t want to come across as some weird, crazed...” she pauses to take a huge sugary swallow of full-fat Ribena, “you know. Trying to fit it all in.”

Friel has managed to fit me in to talk about her role as Holly Golightly in an upcoming stage production of Breakfast at Tiffany’s. But only just. Our interview will take place in the chauffeur-driven car on the way to her fitting, and soon we are speeding through the streets of Windsor, where Friel bought a house in 2000. A giant pair of Hogan shades strapped to her face (“Is it really off-putting if I keep these on? It’s just my eyes are really tired”), she talks in a husky stream-of-consciousness about landing the part. “I was cast on the phone. I was in LA. But the director said, and I didn’t know this about me, that I go off on tangents and speak very quickly, which he felt was key to Holly.”

The director, Sean Mathias, has also said that he thinks Friel will make a good Holly because “she has lots of style and sex, but also a big  heart. And anyone who comes from outside a big city, as Anna does, knows that, to get there, you have to put on a mask”. The tiny ball of brunette tresses and thrown-together designer labels curled up in the car beside me certainly has style, while her reputation as a bit of a sex kitten precedes her (that lesbian kiss, and plenty of gratuitous nudity peppering her career to date). I get the impression that behind those shades, the mask is carefully being assembled. For this serious, slightly strung-out woman isn’t the Anna Friel I was expecting. A plucky, down-to-earth, northern lass — that’s the media persona she’s always projected. This is the girl who used to party with Kate Moss and had a fling with Robbie Williams, after all. But beneath the surface, all freckles, cheekbones and lad-mag-friendly innuendo, there lies an ambitious high-achiever who will work as hard as it takes to prove herself.

Last night, for example, she was filming until 11pm for London Boulevard, a film in which she plays Colin Farrell’s sister. A few days after our interview, I hear that she has had a last-minute call from none other than Woody Allen, and had to cancel rehearsals for Tiffany’s to squeeze in a day’s filming on his latest project — having learnt her lines overnight. She is currently starring with Will Ferrell in Land of the Lost, in cinemas now.

We saw her most recently on the small screen in the Jimmy McGovern drama The Street, and before that in the American show Pushing Daisies, a role that garnered her a Golden Globe nomination and saw the whole family (her boyfriend and fellow thespian David Thewlis, and daughter Gracie, who was aged one at the time) decamp to California. In LA, she says, she regularly worked 17-hour days. When it comes to body image, “you become much more self-conscious when you’re in America”. She is naturally enviably slim (in her Ksubis she has the bottom of a 15-year-old), but I ask if she succumbed to the cult of nutritionists and personal trainers. “It’s accessible and available, so, yes, I did have a trainer, who was also a nutritionist, so she was able to show me what I was doing wrong.” Which can’t have been much.

Friel was back to her fighting weight and on set, filming the movie Goal!, only six weeks after giving birth, “although, emotionally, I don’t think I was right — or at least back to the way I was — for about a year”. Having recently turned 33 (“I spent my birthday in my pyjamas eating bad food”), ageing is becoming an issue for her. She says she worries about being “hot one minute and the oldest slice of bread in the barrel the next”. Her solution is to vary her roles, with the aim of “developing longevity”. Her acting idol is Julie Walters — “wonderful, open, warm and supertalented”.

Friel really warms up when she talks about motherhood, and the glasses even come off when I tell her that I don’t plan on having kids. “Really? I don’t believe you!” I just don’t think it would come naturally to me, I tell her. “Oh, but it would! It just does. I never planned it. All I’m saying is that you’ll miss out on having this beautiful, innocent, adorable little thing that’ll love you like you’ve never been loved before. And it makes everything else just not as important, so you go at things with a lot more confidence.”

Friel credits her own “amazing mummy and daddy, who I talk to every day”, with keeping her feet on the ground. “They’re completely and utterly committed to each other, and they tell each other everything.” While Friel says that having Gracie, 4, has “changed everything” about the logistics of her and Thewlis’s relationship, she also says that “I like her ruling the roost, and dictating what happens”.

She and Thewlis have been together “nine years last week”, but have no plans to get married. And while she admits that her parents’ perfect relationship is “a shining example, it’s also a lot of pressure, because you want to succeed as they have”. Exasperated, she asks: “Is it really such a big deal not to be married these days?” Perhaps, one feels, deep down it is for her. It is the one thing missing from her roster of achievements. “I always thought I would, you know, get married and then have kids. But then I don’t know what happened, it all went topsy-turvy.”

Friel is no stranger to the work pressure, and is her own worst whip-cracker. When I ask what all the hard work is for, she replies that “it’s always just been to get better and be taken seriously. So England can be proud of one of its actresses”. Before we left her house, she told me that Gracie was upstairs watching Muppet Treasure Island, and that “today is one of those days when I’d love to stay at home with her and not have to be anything, or anyone”. And as I watch her hop out of the car, wave goodbye to the driver (“Thanks so much, chuck”) and dash off to her next appointment, I can’t help but hope that she gets one of those days soon.

Breakfast at Tiffany’s opens on September 9 at the Haymarket Theatre Royal, SW1

Anna loves:

Dr Sebagh Deep Exfoliating Mask - 'It gets my skin glowing'

The Book Thief - 'It made me cry'

Mai Lamore shoes - 'I adore my party shoes'

Vodka tonic - 'I pick my own lemons from my garden in LA'

Mr briefcase - 'I've had it for years. I keep all my scripts in it'

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