Kristin Scott Thomas teams up with old pal Ralph Fiennes in The Invisible Woman, which tells the story of Charles Dickens' affair with a young actress. She tells Jeananne Craig why being cast as 'the mother' wasn't all bad - and why director Fiennes was a "terrible bully".

When Ralph Fiennes signed up to direct and star in The Invisible Woman, he contacted old friend Kristin Scott Thomas.

The pair previously played passionate lovers in the 1996 Oscar-winning film The English Patient, and shared screen time in the lesser known 2005 drama Chromophobia. And after watching Fiennes' 2011 directorial debut, Coriolanus, Scott Thomas had told him to give her a call if he got behind the camera again.

This time, however, she wasn't enlisted to play the love interest to Fiennes' Charles Dickens. The actor-director, who at 51 is two years younger than Scott Thomas, wanted her to play Frances, the mother of the author's young mistress, Nelly.

When asked why Fiennes always had her in mind for the character, Scott Thomas confesses: "I didn't know that. That's a bit upsetting. Maybe because she's a sort of ageing actress on the way out!"

The Paris-based mother-of-three may be an ageing star, but there's no sign that she's on the way out, and she's still remarkably beautiful. Despite a painfully early start to catch the Eurostar to London, she is elegant and chic with a dark bob, silky blouse and studded killer heels.

Perhaps it's because of this cool beauty - and the upper crust roles she's often played - that the actress has a reputation as something of an ice queen. Face-to-face in a hushed hotel room, it's clear she doesn't suffer fools, but she's also happy to jest and breaks into laughter frequently.

She appears to have forgiven Fiennes for his casting choice, describing him as "incredibly brave" for taking on both director and leading man duties.

"It was wonderful working with Ralph again. Even though he was a terrible bully," she deadpans. "He used to tell me to stop acting all the time."

Did he want her to seem more natural? "I don't know what he wanted. One day when I did stop acting he said, 'You look as if you want to go home', and I said, 'Yes, well you told me to stop acting'," she recalls, laughing.

Fiennes, for his part, is full of praise for Scott Thomas. "When I offered her the mother's part, she was a little bit, 'Hmm, I'm not sure about that'," he says. "But she gives a brilliant performance in a really key role, because the way that Mrs Ternan negotiates and acquiesces in Nelly's coming together with Dickens is very important."

Based on Claire Tomalin's biography of the same name, The Invisible Woman sees the married author falling for 18-year-old Nelly (played by The Amazing Spider-Man 2 star Felicity Jones, 30), as she tours the country with her mother and sisters, chasing theatre work.

Mrs Ternan is highly protective of her brood, and her daughter's reputation. But Dickens can offer Nelly the financial security that life on the 19th century stage couldn't.

Scott Thomas, who has two sons and a daughter from her former marriage to French gynaecologist Francois Olivennes, could relate to Mrs Ternan's bind.

"You do what's best for your child, even if in her case the decision of what to do must have been really, really hard.

"[Acting] was a very, very hard life and I think that comes across well in the film - how difficult it was having to trudge all the way to different theatres in the middle of the night, endlessly being on trains, living in terrible conditions and not having very much money," she adds.

"If you're not a success, there's nothing really else to do. When she sees that her daughter doesn't really have any talent for the stage, she has to find another way out."

Dickens is trapped in a loveless marriage, and as the film progresses we see him embark on a passionate affair with the intelligent, self-possessed Nelly.

As rumours of their romance spread among Victorian society, the revered author is determined to keep it a secret, and Nelly is destined to remain his 'invisible woman'.

Scott Thomas admits that Dickens behaved "atrociously", adding: "That's the great thing about Ralph's performance. You know he's doing something not great, but you still empathise with him."

While we see Nelly fail to make a dent in the theatre world, Scott Thomas has worked steadily since graduating from drama school in Paris aged 25.

She'd previously attended London's Central School of Speech and Drama, where she didn't have much success, and so moved to the French capital to work as an au pair at 19.

The move paid off. Second time round, Cornwall-born Scott Thomas went on to land roles in films like Under The Cherry Moon in 1986 and 1988's A Handful Of Dust. But her big break came in 1994 when she played icy aristocrat Fiona in Richard Curtis's Four Weddings And A Funeral.

The hit romcom celebrates its 20th birthday this year. When asked how her life has changed since, the adopted Parisienne gives a Gallic shrug.

"Well I'm 20 years older! It's the same and it's different at the same time. I dunno. How long have you got?

"It feels like a lifetime ago," she adds. "It is a lifetime."

Four Weddings did pave the way for her Oscar-nominated role in The English Patient, and appearances alongside Tom Cruise in Mission: Impossible and Robert Redford in The Horse Whisperer.

In recent years, aside from the occasional Hollywood dabble (including the 2009 chick-flick Confessions Of A Shopaholic, an experience she later confessed to hating), she appears to have eschewed blockbusters for lower budget films, movies made in her adopted homeland and stage appearances.

The actress acknowledges that her motivation for choosing projects has changed as she's matured.

"I'm much more interested in working with a director, rather than on a role specifically. I'm more interested by the director's atmosphere and his way of film-making."

With The Invisible Woman, it seems Scott Thomas found both an appealing role, and a good director.

"I'm in awe of what Ralph's doing," she admits. "He's keeping it all in the right place, with everything ticking over, and at the same time he manages to remain one of the team as far as the actors are concerned."

Extra time - behind the scenes on The Invisible Woman

:: The screenplay was written by Abi Morgan, who previously worked on the Oscar-winning Margaret Thatcher biopic The Iron Lady.

:: Fiennes didn't intend to play Dickens when he originally agreed to direct the film. He says: "After quite a few months of working on it, I felt, despite knowing it would be very difficult, that I couldn't resist playing him."

:: He wasn't much of a fan of the author as a schoolboy: "I think I decided Dickens was too cosy, or comfy perhaps. I feel the opposite now."

:: There were blushes for Felicity Jones (Nelly), when she tripped on some sand dunes on her first day of filming. "It broke the ice with the crew!" she admits.

:: Fiennes often had the cast perform up to 20 takes to perfect scenes. Jones says he "doesn't let you take the easy option!"

:: The Invisible Woman is released on Friday, February 21