SO, Morfydd, I ask to begin with, how do you pronounce your first name? “It’s all voiced,” the actor tells me in her soft Welsh accent. “And there’s a trilled R.” She proceeds to show me. “Morrrrrfyd,” the “R” rolling out and sustaining like a Keith Richards riff.

The lesson is timely as we will all be having to learn how to pronounce it soon. Morfydd Clark is about to become a very familiar name. When we speak, she’s in New Zealand working on a top-secret project (she starts whispering when she even alludes to it). We both know that she’s filming the new TV adaptation of Lord of the Rings for Amazon Prime Video and the heavy rumour is she’s playing Galadriel (the part played by Cate Blanchett in the Peter Jackson film trilogy), but she’s not saying anything. “I’m just bound by secrecy,” she apologises.

A few weeks after we speak, she finally confirms that she is indeed playing Galadriel, but this morning (this evening where she is, actually) all Clark will say is that her days involve “lots of physical activity. So, my body is kind of like: ‘What’s happened?’ Having spent most of my life being naturally skinny and doing no exercise, it’s been a big shock.”

It’s possible you may have noticed her already, of course. Perhaps you spotted her in Armando Iannucci’s quirky Dickens adaptation The Personal History of David Copperfield when it came out in January. (But did you spot that she played both David Copperfield’s fiancée and his mother?) Or maybe you caught sight of her playing Mina in Mark Gatiss and Steven Moffat’s gimmicky take on Dracula for the BBC last Christmas. She was also seen in the TV adaptation of His Dark Materials last year.

Indeed, since her first appearance on screen in 2014 (in a couple of episodes of historical drama The New World) Clark has been a regular on both TV and in films such as Pride and Prejudice and Zombies, Love and Friendship and Eternal Beauty (which came out last week).

But if you want a true sense of what she’s capable of, then her new film Saint Maud should be the first place to look. Debut director Rose Glass’s intense, disturbing, psychological horror movie is a perfect showcase for her abilities. Clark plays the title character, a young hospice nurse with deep, and frankly disturbed religious convictions. She becomes the palliative carer for a choreographer played by Jennifer Ehle, who is still trying to live a hedonistic lifestyle despite her diagnosis. Suffice to say, it does not go well.

Read More: Damon Smith's review of Saint Maud

Set in a British seaside town that is all cheap glitter and grime, the film explores desire, obsession, religious belief and monomania while moving slowly, inexorably into darker waters and a climax that is both fated and yet still deeply shocking.

Long story short, it’s very good. And Clark is very good in it. It’s one of those performances that ensure that you will look out for her name in future.

When she read the script, Clark says, she was stunned by it. “It was this mixture of being shocked by every turn. And also, this awful inevitability to what was happening. That was what was really amazing about it.

“Also, lots of my family work for the NHS and I have never had any skills to do that. I didn’t have good grades and I panicked around people who were sick. So, I’ve always been quite fascinated. How do you do it?”

As for the religious side, “my dad’s Northern Irish Glaswegian Catholic, so I have a kind of insight into that world. I wasn’t religious, but people in my close family are. I’ve always been fascinated by the idea that maybe one day I would be.”

In short, Saint Maud could have been written with her in mind. “In terms of the health worker aspect of it and this idea of losing and finding faith … I felt like I had been doing research on them for most of my life; two of my obsessions bound in one.”

HeraldScotland:

As for Maud herself, the film's writer and director Rose Glass recently told Esquire Magazine that her elevator pitch for the movie was "try thinking of Maud as if Travis Bickle were a young Catholic woman living in an English seaside town.” What is Clark's take on Maud? “I would say that she’s someone with a huge amount of conviction who has fallen through many cracks and is probably the loneliest girl in the world.

“I kept on wishing she had got the best part of religion which to me is the community, but unfortunately that’s not the path that she goes down.”

Maud’s saintliness is up for debate, but she certainly understands the idea of self-flagellation. At one point she puts nails in her shoes and goes for a walk. So, Morfydd, how method did you go? Did you slip any nails into your trainers just to get the full effect?

Possibly not. “I’m completely un-method. I would immediately come out of it as soon as the take stopped. It was enough being in her head as much as I was, to be honest. It was quite nice to have a break. The whole crew knew I needed to enjoy those moments when I wasn’t on screen.”

Saint Maud is just the latest of several horror roles in her CV. “I do find I enjoy horror a lot,” she admits. “I wouldn’t say I’m a massive horror buff, but I’ve always liked it. I was reading a thing about how if people are a bit anxious you really like horror because you’re so invested in it. And I do feel that there’s this big catharsis after watching a horror film. That you allow yourself to feel these feelings that you may keep inside all day in the normal world. It’s kind of like, ‘I’m allowed to be scared and anxious and worried while watching this because it’s horrific.’ So, that aspect I really like.”

There’s a reason for that, of course. Anxiety is very much part of Clark’s own story. Born in Sweden and brought up in Wales she was diagnosed with attention deficit hyperactivity disorder at the age of seven. She is also dyslexic. Perhaps no surprise then that she struggled at school before dropping out when she was 16.

“This is not to say all my teachers were awful,” she explains, “but I think it’s very difficult – if you have a class of 30 – to deal with someone who is neurodivergent. And so, I was often being told off a lot and didn’t like authority figures.”

Acting was to prove her salvation. After school, she auditioned for youth theatres, and joined the Welsh National Youth Opera because she liked singing. As a result, she began to see the world in a new light.

“It allowed me to be a bit busy. I started to find authority figures that made me feel safe instead of feeling worried. I think that was really important to me.

“I think if I hadn’t found that my life would have been very different. It was definitely very healing.”

Her dyslexia is less of a problem than you might imagine as an actor, she says. “The layout of scripts for someone with dyslexia is very good. It’s not like opening a novel and seeing all those words.

“I also find speaking words means they go into my head. If I am reading a book, I have to read it out loud, which obviously wasn’t very good for exams and stuff. But in acting it’s good.”

She even found playing Shakespeare helpful. “I kind of relaxed when I was doing Shakespeare because everybody finds it hard. It’s the rhythm and the small phrases. Having dyslexia, you start to have a lack of confidence and disdain for yourself for not being able to do it. And with Shakespeare, it’s like, ‘Well, no wonder this is so hard.’

“And I could work at it and get into it without feeling like an idiot. I think I had begun to be quite cruel to myself about my bad reading.”

She can be hard on herself, I think. Saint Maud will be something of a breakthrough role for her and yet, she says, during the making of it, she feared not being good enough.

HeraldScotland:

“One of my main worries when I’m doing anything is, ‘Am I being really rubbish for the other person?’ Quite a lot of the stuff we started on for Maud was me on my own, so I didn’t have that worry that I was letting anyone down. And now, looking back, it was fortuitous that I didn’t start with my scenes with Jennifer Ehle because I think I would have just been like, ‘Oh no.’”

Clark has now been in New Zealand since last October, which has been “very surreal,” she says in this time of pandemic, “because I’m experiencing it really differently to everyone at home. It’s been an eye-opener as well in terms of how a country can be run very differently to the way our country’s run. I’ve felt very safe here the whole time. There’s been a lot of clarity and it feels like everyone is in it together.”

If only it was the same back home, she says. “There’s so much confusion. ‘Am I doing this right? Am I doing that right?’ I think that’s what’s been really difficult for lots of my family and friends at home.”

Filming on Lord of the Rings was closed down at the height of the pandemic, but it has since resumed. “We are so lucky to be in a country where it’s not as bad as others,” Clark says, “and it’s not as bad because people have been really careful.”

The Amazon series, helmed by the Spanish director JA Bayona, best known for The Impossible and the most recent Jurassic World movie, Fallen Kingdom, is a big deal. Some have estimated it might cost up to $1billion (more than £770m) to make. Rather more than the makers of Saint Maud had to work with. That does suggest that Clark is moving into new territory.

And yet it’s clear that Clark still hasn’t entirely shaken off the shadow of her younger years. Her childhood and those teenage years continue to shape her. Rather like Maud, fear might be stronger than desire in her.

“I’ve always been not very ambitious because I’ve been so scared of failure, I think,” she says. “I’ve always kept my goals really tiny and then try to be surprised. I don’t know. I personally find ambition quite a frightening prospect because to me it’s linked to failure. I never enjoyed having goals. I’ve always enjoyed wobbling along.

“I think not doing very well in school means your expectations for yourself are very low and in this career that has proved very, very helpful to me. I’ve gone through being very pleasantly surprised.”

If her performance in Saint Maud is anything to go by should get used to that feeling. And the rest of us need to practice saying her name.

Saint Maud is in cinemas now