Who: Kristin Scott Thomas
What: Lady Elizabeth Boleyn in The Other Boleyn Girl
Key roles: Under the Cherry Moon (1986), Four Weddings and A Funeral (1994), Gulliver's Travels (1996), Mission Impossible (1996), The English Patient (1996), The Horse Whisperer (1998), Life As A House (2001), Gosford Park (2001), Keeping Mum (2005), The Golden Compass (2007, voice of Stelmaria).
She may play quintessential English women to perfection, but Kristin Scott Thomas does not have national-treasure status in England. For starters she's rarely done British TV. Secondly, she has lived in Paris since she was 19 and considers herself French. Thirdly, she has a reputation for being as posh and chilly as a draughty stately home.
Which is all rather unfair, as she is a fine and versatile British actress and rather good fun to boot. This morning she has pitched up for the photo shoot in a Paris hotel without the entourage typically surrounding high-maintenance actresses.
"Are you sure I don't look like a barrage balloon?" she says, dubiously smoothing down the gorgeous but undeniably flouncy dress from Dior that the fashion team has picked out for her.
All this to publicise a film in which, to be honest, she doesn't have the biggest part. The Other Boleyn Girl features not one but two young Hollywood stars - Scarlett Johansson and Natalie Portman - who play the Boleyn sisters. Based on Philippa Gregory's historical novel (which was adapted for television in 2003) and directed by Justin Chadwick (previous credit the addictive Bleak House), it tells the story of Anne Boleyn's sister Mary, who was also said to have been a lover of Henry VIII and may have borne him an illegitimate son.
It combines sumptuousness - the costume design is by Oscar-winning Sandy Powell - with a brooding and sinister portrait of a Tudor family in meltdown.
Scott Thomas' role as the girls' mother provides the moral backbone of the story and she carries it off with the austere aplomb we've come to expect of her, despite the fact that the Sandy Powell headdresses were "nightmarishly uncomfortable" and she was wearing a pair of Northwest walking boots under her crinoline.
The fashion shoot is over and she's stretched out on an armchair in the hotel room, having changed back into a pair of skinny jeans and a T-shirt.
"I didn't think I had a big enough part. But they said they'd give me more to do, and when I heard Mark Rylance [he plays her husband] was in it, too, I caved in."
She won ecstatic reviews for recent stage parts, including Madame Arkadina in a revival of The Seagull at the Royal Court Theatre in London last year, and was recently hailed by Harvey Weinstein as one of the greatest actresses of her generation. Despite this, she maintains a surprisingly workmanlike approach to choosing parts. This might partly be attributable to the fact that since she split up with her husband of 17 years she must share the childcare arrangements for their sons Joseph, 16, and Georges, 7 (daughter Hannah, aged 19, is a student in London).
It has been more than 20 years since Kristin Scott Thomas became a professional actress, but there is a sense that it's only recently she has become truly comfortable in her own skin. Her co-star, Hugh Grant, did her no favours by saying that she needed to be warmed up every morning on the set of Four Weddings and a Funeral. She stole the movie from drippy Andie McDowell by playing the abrasive but lovelorn Fiona. However, the permafrost reputation stuck. It's partly, I think, to do with the way the camera loves her grown-up beauty - the refined cheekbones, more angles than an egg box, the languorous eyelids, her luminous complexion (inherited, she says, from her grandmother). In person, by contrast, she seems softer, relaxed, almost girlish.
"I don't want to go into details," she says, fidgeting with her hair, "but I have had a pretty rough time recently. I feel like I've climbed a mountain in some way. I've realised that I am who I am and that is it. Like it or lump it. I'm not around to please anyone any more, and it's a huge relief."
Reading between the lines, she seems to be discreetly referring to the end of her marriage to Francois Olivennes. For years she had referred to her husband, a world-renowned fertility doctor, as "my rock". He was the man who was at her side through periods of depression, helping her overcome an ingrained sense of abandonment that stemmed from childhood. The relationship lasted a long time, but four years ago she was linked, albeit briefly, with Tobias Menzies, an actor 14 years her junior. She seems to hint that, like many couples who meet when they're young, she simply outgrew married life.
"Now I can be the mother I want to be, the woman I want to be, the actress I want to be. I am afraid that all this has happened to me with getting older. I'm 47 - unlike most actresses, I don't lie about my age - but I'm liking this bit. I love it. I wouldn't swap it for a million years."
It's no wonder that, after the horrors of a difficult break-up, she feels a sense of liberation.
"I don't feel single. You don't when you have children. But I do feel more independent. Single has a boyfriend connotation ..." she fades away at this point. "But independence is great. I don't have to check in with anybody. After a long time with someone, you realise you've been thinking for two."
She became famous - or "had my moment", as she self-deprecatingly calls it - relatively late in her career, at the age of 35. Four Weddings and a Funeral was followed closely by the role of Katharine Clifton in The English Patient, for which she was nominated for an Oscar for best actress.
They were very different films but the melancholic, indulged posh-girl persona stuck.
She grew up on naval bases in Yorkshire and Dorset. Her young mother, brought up in Africa and Hong Kong, was unprepared for life in England. Her father, a Royal Navy pilot - "so handsome. Absolutely gorgeous" - was often away. They lived in a small village, population 300, where the principal entertainment for Kristin was going to the local shop dressed as an elderly dowager. Then, when she was 5 years old, her father died in a plane crash. Her mother was pregnant with her fourth baby.
Kristin, an odd, insular little girl at the best of times, remembers being told not, under any circumstances, to cry. She was hopeless at making friends - "too poisonous, I suspect." She did what any sensible child would do and escaped into a fantasy world. "I had an imaginary friend. Her name was Wendy. Wendy came from a very, very rich family and they had a Rolls-Royce."
In a horrible coincidence, six years later her stepfather - also a pilot - died in a freakishly similar accident. "This was in the days before 'counselling'. I hate that word so much! You just didn't discuss it.
"Nobody talked about it. And because it was a naval affair and we were a naval family it happened all the time. All the time. You just kept going and it was very tough."
When her stepfather died, she was sent back to school on the train three days later. Boarding school, including a stint at Cheltenham Ladies' College, was grim.
"I was very lost as a teenager," she says, pulling a face. "Which is a horrible way to feel." The only blessing was that her mother ended up being too impoverished to pay the school fees, so she was allowed to go back home.
"I am sure that, had I grown up with both parents, had I grown up in a safe environment, had I grown up with a feeling of safety rather than danger, I would not be the way I am."
For a child who only ever got to play the wise man in the nativity play, acting might not have been an obvious career choice. However, she was accepted on to the teaching course at Central School of Speech and Drama.
When she realised she wanted to act and not teach, one of the lecturers told her she'd have better luck joining her local amateur dramatic society.
At 18, she was living above a fish and chip shop in London, working at Selfridges. It's difficult to imagine now, when she routinely makes the ubiquitous 50 best-dressed lists, but she was, she says, overweight and depressed.
"I was very, very shy. Very uncomfortable. But I felt I had to get out of London, where I was being taunted by this idea to be an actress.
"I knew in London that it wasn't going to happen because I didn't have the courage and I was told I didn't have the talent."
She headed for Paris in a bid to start again. "I didn't have a clue what I was going to do. I'd heard about a job being a slave at French Vogue, but I was too scared to make the calls."
She finally found work as an au pair for a couple who were in the opera business. "That's what got me out of my rut. It was hard work and my boss asked me what did I really want to do? I was forced to ask myself: 'are you going to be an au pair for the rest of your life?"'
She won a place at Ecole Nationale Superieure des Arts et Techniques du Theatre, and apart from taking time out to have children, she's barely been out of work since she graduated.
The odd thing is that there's a striking ambivalence about Scott Thomas' attitude to her professional life, despite the fact that she fought so hard to become an actor. On the one hand she has a reputation on both sides of the English Channel for bringing an intelligence and subtlety to whatever role she takes on. In France, she gets to play a far greater variety of parts than in class-obsessed Britain; she's just finished a film in which she plays a convict who has committed a terrible crime.
"I loved it. No makeup. I hardly even speak."
On the other hand she claims that all she really wants to do is stay at home and choose wallpaper samples for her new top-floor apartment. Unlike many actors, there's a sense that she can see how ludicrous elements of her job might be.
"The weird thing about me, is that I have chosen this job that takes me away all the time. When all I want is to be at home."
It's an ambivalence which goes all the way back to when she was 25. She starred as a topless socialite in her first Hollywood movie, the much derided Under the Cherry Moon with Prince. The pop star had spotted her at a routine audition in Paris not long after she'd graduated from drama college, and suddenly she found herself sat in a movie trailer working on a project which she knew, in her heart of hearts, was awful.
"I remember one of the producers suddenly bursting into my trailer and saying: 'Do you want to be a star?' I thought that was the most extraordinary question. My initial reaction was: 'No, no I don't.' But then I thought: 'Hang on. Can you just let me think about it?"'
On Monday she's off to the town of Reading, west of London, to start filming Noel Coward's Easy Virtue, in which she will play snooty Mrs Whittaker opposite her colonel husband, played by Colin Firth. "Here we go again! Give me a horse and a country pile!" she exclaims, gently poking fun at herself, which seems to be her default position.
"I swore on my children's heads that I wouldn't do yet another English 30s film after that Robert Altman thing" - the Oscar-winning Gosford Park - "but people just keep asking me to do it!"