Katie McGrath repeatedly sells herself short. It's an attractive trait and, heaven knows, we'd rip her to shreds if she was cocky. But there's a balance to strike and, right now, it's tipping over. A few spoonfuls of arrogance wouldn't go amiss.
Ask her to recount the strangest story she's ever heard about herself and she nearly hyperventilates with laughter as she talks about a rumour linking her to the role of Anastasia Steele in 'Fifty Shades of Grey'.
Apparently it's the most preposterous notion she's ever heard, because by her own admission, the Ashford-raised star couldn't possibly pull off a performance as a billionaire's whipping girl.
This is puzzling considering her saucy screen debut as an obliging maiden to Jonathan Rhys Meyers' Henry VIII in 'The Tudors', many moons ago.
"I was honoured when I heard that," she says of the 'Fifty Shades' rumour. "I'm genuinely interested to know who they're going to cast – I think everyone is – but there's no way I would be suitable for [the part of Anastasia]. I'm too... I don't know, I'd end up laughing my way through any scenes like that.
"They're probably going to make it quite graphic and all I'd be thinking about if I got the part would be when anyone brought it up. 'Oh hi, Katie, you were great in 'Fifty Shades of Grey'' And I'd be like, 'Really, what was your favourite scene?'
"Anyway," she adds, "I love all these rumours; they're great fun. That 'Fifty Shades' stuff was up there with another story that I was in the running for the new 'Transformers' film. And you bet your money I want to run round with giant robots," she snorts. "But that was never going to happen. None of it is."
Well, Blessington's Jack Reynor ('What Richard Did') recently landed a role in the franchise, so it's not out of the realms of possibility.
"Who would ever want to be the person to follow in the shoes of Rosie Huntington-Whiteley and Megan Fox, easily the most beautiful women on the planet. Not me. I'm nowhere near that brave," she says.
McGrath is great fun to interview and, from secondary sources, a hoot on set. 'Merlin' co-star Colin Morgan called her "a troublemaker" and Andrea Riseborough labelled her "a joy" while working together on Madonna's surprisingly watchable Wallis Simpson epic, 'WE'.
She's an example of charm and graft; someone who took a stab at several careers before 'bluffing her way', as she puts it, into acting.
"It was more that I was sort of meandering along, not knowing exactly what to do with myself," she explains, speaking to 'Weekend' from her home in Fulham, London. "So I just thought I'd try everything; see if it fit."
There was a history degree at Trinity, and a placement at 'Image' magazine that didn't quite work out, even though she had once professed a desire to spearhead the editorial department of 'Vogue China'.
"It was a bizarre ambition, as I didn't speak a word of Chinese," she has said in a previous interview.
In a story that has been spun out a few times, her mother's friend later landed Katie a position in the wardrobe department of 'The Tudors'. Her raven locks, glassy stare and lithe posture caught the eye of a casting director and soon she had a short scene as a lover of Rhys Meyers' Henry VIII.
McGrath found her calling. "I obviously knew 'The Tudors' crew well and one of the drivers gave me a confidential cast list with all the actors' agents' contacts on it, and I wrote to every single one. That was like gold dust to any actor."
A London agency spotted lucrative potential, shipped her off to a BBC casting call and, despite her inexperience and lack of professional training, she landed a starring role as the bewitching Morgana, Camelot's resident evil sorceress.
Sometimes, McGrath believes it was her greenness that paid off.
"If I was going to advise anybody wanting to be an actor now, I wouldn't suggest going to drama school, not unless you particularly want to do theatre and that's really your passion. Do an arts degree, any type of degree, and then see how it goes," she says.
"Most of the people I know didn't do a drama degree. Learning the ability to work, that's what's important as an actor, and you don't learn that there, in my opinion."
'Merlin' – which sold to 52 broadcasters in 180 countries, including China and the US – has finally come to an end after an admirable five-season run. At last, the actress (29) is free to spread her wings.
While another 'Merlin'-like fantasy epic, the recently aired 'Labyrinth', heralded her first post-BBC venture, it's her casting as Lucy Westenra in NBC's small-screen adaptation of Bram Stoker's 'Dracula' that's really got our attention.
Currently shooting in Budapest, McGrath portrays an aristocratic social butterfly and best friend of Dracula's muse Mina Murray (played by newcomer Jessica De Gouw), who'll become entwined in a web of lies, lust and temptation during the course of the series.
Oh, and wouldn't you know, look who's playing the bloodsucking caped crusader – it's only her old pal, Jonathan Rhys Meyers.
"'Dracula' is one of my favourite books. The chance to play Lucy, alongside Jonathan, is just phenomenal – I would kill for that part. And thankfully, I didn't have to," she chuckles.
"After working for so long on 'Merlin', I would jump at the chance to work on a series like this. I'd always love, of course, to work with Jonathan again; he's an amazing actor."
It all seems to come back to Jonny. McGrath's first ever scene was with the pouty Corkonian; they were linked romantically several years ago, and now, she's starring opposite him in a new series. People will talk.
"First, we were never together," she says. "Always just good friends and still are, but he's been incredibly busy with his work and been all over the world – it's been hard to keep track of him. So to get a chance to work with him again, to have that familiarity, is too perfect. And on a classic story like this, amazing."
After 'Dracula', what comes next? Surely McGrath, who's inexplicably single, has kept Hollywood waiting long enough? There must have been several enquiries after a brief, eye-catching performance in Madonna's royal epic, 'WE'?
The Material Girl herself claimed McGrath was "mesmerising with a face straight from the golden era of Hollywood" and "one of the most beautiful women" she'd ever seen.
"Are you joking?" she exclaims. "That's a nice story but, c'mon, you're not going to get me with that."
Revealing our source as co-star Andrea Riseborough, she still struggles to take the compliment. "I mean, that is just lovely, but my God, Madonna, or Andrea, was probably mixing me up with someone else. It's a pretty amazing thing to hear on a Monday, you've definitely made my day ... or my life, really."
Has she stayed in touch with Madge?
"She was amazing to be around, an inspiring presence on set and works so, so hard, I really was in awe of her," says McGrath. "You did have to pinch yourself every now when you were talking to her in the beginning, but she's so disarming and lovely, you kind of get over that.
"But are we in contact? Let's just say, I doubt I'm on her speed dial."
While London is home for now, McGrath is hankering for a more localised project. "I'm happy where I am, and relocating to LA is not an option for me right now," she says.
"I'd love to be able to work at home in Ireland, on an Irish film or something on RTE, because I miss it so much. But there's not a huge amount going on, so I don't know when that will happen."
Something on RTE, even after 'Fair City' reportedly once turned her down for a role many moons ago?
"Now, I wasn't turned down for a part. I just sent a tape and CV to them and never got an audition. I sent a tape everywhere," she says.
"But a stint in Carrigstown, I think I'd quite like that."
'Dracula' starts on Sky Living in the autumn