Left: in Downton Abbey

Today, in an artisan coffee shop near the King’s Road, the actress is playing it so low-key, I feel myself willing her to ham up the enthusiasm. It’s not that she wasn’t grateful to be there – she certainly enjoyed the experience, heck, she even mingled her way around the pre-awards-bash party circuit – it’s just that tenacious schmoozing isn’t really her bag.

“I’m not the kind of person to sell their grandmother to get where they want to be,” she admits, taking a sip of mint tea. “I don’t want to push myself on people if they don’t know who I am from Adam, but to get introduced to somebody that I’m, you know, a little in awe of, I am absolutely happy to stand and have a chat.”

Like her alter ego Anna Bates – Downton’s head housemaid and lady’s maid to Lady Mary Crawley – Froggatt values discretion and won’t divulge who her famous fans are. She is a somewhat reluctant celebrity: a 33 year old who’s not interested in the bells and whistles that can come with an acting career, and no amount of showbiz hoopla is going to change that. Her surname, for starters, inherited from parents Annie and Keith, is lacking the brand glamour usually found in the Equity directory and, while other ingénues may have traded it in for a more exotic stage name, North Yorkshire-born Joanne has stayed loyal to her roots.

But Downton must have changed something. Moving on, I press her on the impact of the megabucks she’s surely banking from the show’s huge international success… A notion she immediately dismisses. “Far from it!” she chuckles, wafting a wrist full of silver beaded bracelets. “People assume that, with all the Baftas stuff, you're super-rich. But, no, we’re not. The State’s [TV] industry is so much bigger that people there in successful shows probably earn 20 times what you can earn in the UK.” So modest is her lifestyle that after marrying her computer programmer husband James Cannon last October, they forwent a honeymoon in order to renovate their four-bedroom house in Buckinghamshire. It’s the same area in which her close friends all live and where she can be found watching Murder She Wrote – her guilty pleasure – with a cup of tea and a chunk of chocolate. “Very rock’n’roll,” she laughs.

If the series hasn’t brought unimaginable wealth, it’s certainly opened doors career-wise. Over the next few months, the former Coronation Street star, whose CV boasts Brit TV favourites Bad Girls and Life On Mars, will be appearing in two British films: alongside Jaime Winstone in uwantmetokillhim? and James McAvoy in an adaptation of Irvine Welsh’s Filth. She also won a British Independent Film Award for Best Newcomer for her role in 2010’s In Our Name (ironic when you consider she has been an actress since age 16, but impressive nonetheless). Tellingly, it’s also been less than 24 hours since she flew back from LA – her ears are still popping and every so often she apologises as she pauses to pinch her nose and blow out her cheeks – where she has just signed a new Hollywood agent. You feel that this could be a turning point in the Redroofs Theatre School graduate’s career – if only she gets the right breaks. Not that she’ll admit to having a five-year plan. “By the time I get to 85 I want to be well-respected,” she says. “I guess that’s my 55-year plan!”

When she isn’t working, travelling is high on her priorities. Vietnam, China and Cambodia are on her must-visit list and, as she reveals she’s visited Ibiza twice, I see, for the first time, the flicker of a wild child within. She is a fan of Space and Pacha and tells me the 5am-ers are no problem. “You can snooze on the beach. You go out late, so you’re on a different time scale.”

Before meeting James, Froggatt embarked on a tour of Australia following filming of Murder In The Outback in Sydney (her favourite city in the world) – a 2007 drama in which she played murdered British tourist Peter Falconio’s girlfriend Joanne Lees. “I’m not afraid to roll my sleeves up and get on with it. I went to Glastonbury a few years ago and did five days with no shower, there was no VIP – I had mud up to the top of my wellies. I absolutely loved it!”

Noting my visible surprise, she tells me she gets a kick out of doing things that scare her. On one occasion, while on safari in Africa, she almost came face to face with a lion. When I tenuously link the encounter to the Sharknado phenomenon that recently whipped social media into a frenzy, the reference is lost on her and she looks at me blankly – she’s not on Twitter and she recoils at the mention of it. “You have to be very careful of what you put on those things,” she says in a soft Yorkshire accent. “Once you start commenting on things in a public way, [like] any big events in the world, you feel like you have a responsibility to [keep] commenting on things. I don’t know if I ever want to be put in the position where I’m forced to [talk about] something I don’t necessarily know enough about. I guess I think it’s just a bit dangerous, because it can get you into trouble.” I’m pretty sure Anna Bates would approve.

uwantmetokillhim? is in cinemas from 6 September. Filth is released in Scotland on 27 September and across the UK on 4 October. Downton Abbey returns to ITV next month

Joanne Froggatt: Preserving her modesty