Joanne Froggatt on ITV thriller Liar, the Downton movie and why she'll never be a Hollywood star

Joanne Froggatt, the actress who played lady’s maid Anna Smith (later Bates) in all six seasons of Downton, takes up the story. “It was incredible. We went to the Oval Office, and the Situation Room. There was no situation, so it was OK! I don’t know if I’m supposed to say we were in there, so this is an exclusive for Radio Times!”

In person, Froggatt is an appealingly impish presence, and she brings this same mischievous twinkle to her acting. It’s little wonder, then, that at the age of 37 she is among our most in-demand TV actresses. Froggatt, who two years ago won the Golden Globe for best supporting actress for her performance as Anna, knows what to thank for her high profile. “Downton Abbey has changed my life. Having opportunities to do amazing things like tour the White House came from doing that show, and I’ll always be grateful.”

However, Froggatt laughs, she was not an overnight success. “I’d already been working for several years when I got the role of Anna, so I know I can’t take anything for granted.”

After growing up near Whitby in North Yorkshire, where her parents had a sheep farm, Froggatt attended Redroofs Theatre School in Maidenhead, also Kate Winslet’s alma mater. She took jobs in a café, a fish restaurant and WHSmith before making her TV debut as a teenage prostitute in The Bill in 1996. The following year, she landed the role of Zoe Tattersall in Coronation Street.

Froggatt went on to shine in a trio of strong real-life dramas, Danielle Cable: Eye Witness, See No Evil: The Moors Murders and Murder in the Outback. Then in 2010 came her really big break in Downton Abbey.

Froggatt’s profile benefited from the fact that Anna was one of Downton’s best-loved characters – which made the moment when the character was raped all the more shocking. The actress, who lives in Buckinghamshire, recalls what it was like to be the epicentre of a tabloid tornado. “I didn’t expect that scene to be so controversial. I suppose people didn’t expect a show like Downton to tackle the subject of rape. You don’t see too much of those sorts of things in period drama.

“But sexual violence against women is a horrific thing, and the fact that the press and audiences seemed shocked, shocked me. I don’t know why as a society we find that subject so shocking to talk about. The more we talk about it, the better.”

Froggatt’s current clout is underlined by her latest role. The performer, who married her partner James Cannon in 2012, stars opposite Ioan Gruffudd in Liar, a new ITV thriller with more twists and turns than an Andean path.

Scripted by the writers of the moment, brothers Harry and Jack Williams – who were also responsible for The Missing, One of Us and Rellik – the six-part series centres on how different people have different views of what constitutes “the truth”. It asks: are there always two sides to every story?

In what people are calling a “post-truth” world, it seems like an apposite question. Froggatt plays Laura, who she describes as “a modern, confident woman living in a nice place with a nice career as a teacher.

Everything is going pretty well for her. She’s just split up from her long-term boyfriend because he wasn’t ‘the one’. She feels free and empowered after taking control of her life. She’s very intelligent and knows her own mind.

“Then she meets a charismatic surgeon called Andrew [Gruffudd]. They go on a date, and that night changes both their lives for ever. The drama is about the complexity that arises when two people have a very different opinion of a certain event. How can other people tell what really happened? Who is telling the truth? Who is lying? And how does anyone really know?”

This new role underscores Froggatt’s versatility, already evident from her performance last year as Mary Ann Cotton in ITV’s chilling drama, Dark Angel.

Cotton was Britain’s first female serial killer. In March 1873, she was convicted of murdering three of her husbands by poisoning their tea, in order to benefit from their insurance policies.

She is a character very far removed from the saintly Anna. Indeed, Froggatt landed the role as a direct result of portraying the angelic lady’s maid. “When Downton came to an end, someone asked me what role I would like to do next, and I jokingly replied, ‘Something completely different, like a murderer’. And the producers of Dark Angel immediately sent me the script!”

So, what’s next for Froggatt? She has been scouting for work in America, landing a role opposite The Wire’s Wendell Pierce in a film called One Last Thing. But she’s not expecting to land a blockbuster.

“I’m not a big-budget Hollywood type. They want the model type, classically beautiful, and I’m not.”

She says the much-mooted Downton Abbey movie is still very much on the cards: “It’s been tricky. There has been a lot of goodwill from all of us, but logistically it’s a bit of a minefield. It’s very difficult to get all 22 actors together. But if we can, everyone would like to do it.”

Otherwise, she says, “I’ve just been offered something, but I can’t talk about it yet.” Ah, so is she going to be the new 007? “Oh, you’ve got me! I’m obviously going be the first female James Bond. Move over, Daniel Craig! You can quote me on that!” Another Radio Times exclusive.

Liar is on Monday at 9:00pm ITV