Just one look from Morfydd Clark can evoke an unnerving spectrum of emotions, such is the potency of her gaze. In Saint Maud – A24’s brutal and erotic psychological horror – with a blink of dejection and a curdled brow, her expression opens like a vista clearing after rainfall, and the heart sinks with empathy. And in the next heartbeat, her eyes blacken with malevolence, pupils threatening a biblical flood of darkness; it’s a sensational and shudder-inducing skill, alternating with exhilarating unpredictability in the duration of the film.

The feature debut of writer-director Rose Glass, we follow Maud (Clark), a stern and mysterious private nurse who has recently converted to Christianity, and is tending to ex-dancer and choreographer Amanda Köhl (Jennifer Ehle), who is dying from stage 4 lymphoma in a dreary British seaside town. Maud makes it her mission to ‘save’ Amanda, who, in her eyes, is a belligerent sinner partaking shamelessly in the sins of the flesh (you know – sex, booze, smoke-filled soirées, the rest of it).

“Nothing worthwhile ever comes easy”, Maud reminds herself (and us?) in prayer position, earnestly on her knees with hands clasped, as she embodies her calling of spiritual saviour. But her reality is distorted, her vision blurred, her holy revelations back-breakingly orgasmic, and her dedication marked by gory spiky footwear (modern-day self-flagellation, if you will).

Welsh actor Clark – who is swiftly establishing household name status with credits in Amazon’s forthcoming Lord of The Rings series, Craig Roberts’ majestic Eternal Beauty, and BBC One’s His Dark Materials screen adaptation) – is a nightmarish tour de force, her moments of true brutality searing across the screen like flashes of lightning. And wait for the rapturous final scene, so utterly chilling and batshit you can hear the blood pounding in your ears for minutes after the credits roll.

We caught up with BAFTA Rising Star nominee Clark and talked about how she watched Taxi Driver to prepare for the role, subverting tropes of the “mad” sexual woman, and how “seeing grown men afraid of [her] is [her] greatest achievement”…

Congratulations on Saint Maud! It is a film that builds such a simmering sense of dread all throughout – how did you first get involved with it?
I first heard about it from my agent who was super excited about the script and called me saying, “I’ve just read the most incredible script; you have to read it”. It was being cast by Kahrmel Cochrane who cast The Witch and so many other interesting projects, so that made me very excited. I’m not normally very good at reading for long periods of time, I have to work through scripts in small chunks, but with Saint Maud I was just gripped from start to finish.

What was your reaction when you read the script? Were there any scenes or pieces of dialogue in particular that stayed with you or chilled you?
I was just really excited. I could really picture this character that Rose had created and thought that I could bring something to the role. The first script wasn’t exactly the same as what we ended up filming or what ended up on screen, but the one scene which was in the original version and made it to the film which really stuck with me was the party scene. I think, although you don’t necessarily agree with what Maud’s done, that is the scene where you feel the most empathy and sadness for her, and where the power dynamic between Maud and Amanda plays out in a really interesting way. I think that there are a lot of private carers that don’t get treated well and that scene explores how poisonous that can be.

Maud could be perceived to be such an insidious character with a somewhat terrifying past that the viewer slowly finds out about, but you also feel sorry for her – what drew you to the character?
There are a lot of health workers in my family although this year has really shown the world the pressure that they are under and the way that they can be undervalued, that’s something I’ve always been aware of. I think Rose has left it up to the viewer, but I’m not sure that Maud’s past is necessarily “terrifying” in a horror film kind of way, more in the way that 2020 has been terrifying. When health workers burn out – which they have been doing more and more in the UK due to cuts – then terrifying things can happen, either because mistakes happen or because people’s empathy gets eroded. I think Maud’s character exposes one facet of that story, which was really important to me.

Did you relate to her in anyway? And what did you do to prepare for the role?
I related to her in the way that she desperately wants to do the right thing and often ends up doing the exact opposite. I think we can all relate to that to some degree but as someone with ADHD, I often say or do the wrong thing – particularly at school, sometimes without even realising what it is I’ve done. So, I related to that side of her. I think doing both Saint Maud and Eternal Beauty has made me want to be kinder and less judgemental.

Rose gave me a list of films to watch to prepare more for the tone and feel of the film – quite a varied list, really, including things like Repulsion, Prevenge, Taxi Driver, Ingrid Goes West – but in terms of preparing for the character I prefer to work in my head, generally. I was lucky in that I had quite a long period in between getting the role and when we started filming, so I had a lot of time to just sort of have Maud in my mind and build her up over time.

It’s a film packed with religious iconology, akin to The Exorcist, were there any weird events or happenings that happened on set?
Not really. It’s funny, because it’s such a sad and unsettling film, people imagine that it was a very intense and serious filming process but actually it was a lot of fun.

What’s interesting about the film in particular is the way it looks at the idea of dual lives, that we can be one way and go home and be another way – what did you find interesting about this?
I think that was the first kernel of the idea in Rose’s head, exploring this idea that you can never really know what’s going on in someone else’s mind and that what we see can be very different to what that person is actually experiencing or perceiving. I think that’s at the heart of a lot of stories and storytelling that people connect with – whether that’s something like Saint Maud or like Peep Show or even just relatable memes on social media – it’s always fascinating to get an insight into someone else’s worldview and thoughts and to think either, “oh my gosh, me too!” or the opposite extreme of, “I can’t believe that’s what they’re thinking!” I think that both of those feelings are very satisfying.

Also I loved how there is no shying around the female violence – it’s raw, bold and really unbridled – did you love this aspect?
I loved that female grossness was shown in the scab picking and just how messy and dirty Maud’s environment becomes. I think often that women on film have to have beautiful madness and be beautiful in death.

Obviously in the film there are the obvious metaphors and religious references, but there are also others, exploring sexuality etc, what were your favourites to enact, and what do you hope the viewer picks up on?
When I first read the script, one of the first things that struck me was how it subverts and questions this trope that has existed in literature and film for a very long time of the sexually “wild” mad woman. I think that crops up a lot in all kinds of guises and is often presented in quite a titillating, dehumanising way, or in a way that lets the men in their lives off scot-free for what is sometimes actually exploiting someone in a vulnerable state. Though there are sexual themes in the film and Maud is a sexual character, she is definitely not a sexy character. That was very liberating for me as an actress.

I don’t want to talk too much about the plot but I think Rose had done a lot of really interesting things with Maud’s sexual experiences with men vs women vs God in the film, and I hope that audiences engage with that and it can spark some interesting discussions.

The explosive ending is unlike anything I’ve ever seen – how was it to film and what do you hope viewers take from it?
I am too scared to talk about the ending because I don’t want to ruin it!

What was the most challenging aspect of filming something like this?
It was actually really fun to film. Rose and Oliver created such a supportive and nurturing atmosphere from the very beginning, making sure that every single person on set felt valued and like they could approach Rose and Oliver with any concerns or issues they had. And then Jennifer Ehle is also such a kind, supportive person and she really took me under her wing and made me feel comfortable and free to explore Maud’s character and her relationship with Amanda. I think that I would have given a very different performance if I hadn’t been working with someone like Jennifer.

We were also lucky in that, because the settings are so contained, we were able to film a great deal of the plot in chronological order so that really helped in terms of settling in to the character and having her develop organically as we filmed. The most challenging part was probably just that Maud’s story – and thinking about all the Mauds that might be out there struggling on their own – just makes me quite sad.

All your roles have been so incredibly varied, but ultimately inimitable, what do you look for in a role?
To be honest, I think this is quite a tricky question for a lot of actors because you really just take what you’re given. I have definitely been very lucky to have had such varied parts and to work with so many interesting people, and to have had such an amazing team of agents finding me those kinds of roles. I’m only really just getting to the stage where I can actually choose my roles and it’s quite daunting, actually. I would definitely like to do more comedy, as I loved working on The Personal History of David Copperfield so much and I love watching comedy myself. I suppose I look for roles in scripts that grip me and where, as I’m reading it, I think, “Yes, that could be me.” You don’t often get that feeling and when you do it’s really exciting.

You are marvellously terrifying in the role – have you had any friends or families say in a humorous way that they see you in a different light now?
Ha! Thank you! Most of my friends and family haven’t seen it yet so I’m keen to hear what they think! I think it will be weird for them in that all my other parts have been fairly small, so for people that know me it’s just like, “Oh, there’s Morfydd!” and then it’s over, whereas with Saint Maud there’s time for them to maybe forget that it’s me and get into the story.

The idea that I can be scary has definitely been a really fun part of the film coming out and being at the first screenings. Seeing grown men being afraid of me was never something I thought would happen and is my greatest achievement!

SAINT MAUD is out this Friday, 9th October.