British actor Raffey Cassidy has been in blockbusters (“Snow White and the Huntsman”), prestige TV series (“Mr. Selfridge”) and is busily establishing her arthouse resume, with such films as “Vox Lux,” “The Killing of a Sacred Deer” and now “The Other Lamb,” from Polish helmer Malgorzata Szumowska. An eerie thriller featuring Cassidy as Selah, a teenager who comes of age in an all-female cult holed up in the wilderness led by the Shepherd (Michiel Huisman), the film follows Selah’s development, as a “lamb” in the cult’s flock, to a young woman whose choices lead to freedom. “The Other Lamb” debuted last year at Toronto, but its theatrical run in the U.S. was cut short by the coronavirus pandemic. She also starred in “Nightwalk,” a short directed by Szumowska as part of fashion house Miu Miu’s Women’s Tales series. Her work with Miu Miu on the short is an extension of her interest in fashion: “Having worked in films and having been exposed to amazing costume designers sparked my interest in fashion,” she says. “You can say so much about yourself through clothes.”
Where are you spending the coronavirus quarantine?
I’m at home in Manchester with all of my family.
How are you passing the time?
I’m taking up the new hobby of learning to play the piano. I’m certain it will be useful!
Are you watching anything in particular?
There’s something over here on the BBC called “The Nest,” and it’s so good, but it’s on every Sunday so we have to wait a week for the next one. That seems really old now, it’s like, “uh, I want to move on from this because I hate waiting.”
Me and my brother watched “The Fighter.” It’s one of my favorite films now.
What attracted you to “The Other Lamb”?
Honestly, I think the fact that it was kind of this crazy arthouse thriller was one of the things that really attracted me to this script. It’s twisted and so wrong in so many ways and also, although it’s not specifically based on a true story, this stuff actually happens, so there’s so much research I could do. It’s such an interesting story to tell, and getting to play the character that drives the story I found interesting. At the start of it you can’t see that she’s very strong, but then she starts to develop and grow. I found it was something that I wanted to take on; I wanted to be challenged.
Your resume is full of challenging roles.
At my age now  there are lots of parts for teenage girls playing “the daughter,” so when you come across a script like this with a strong character it’s a very rare thing.
There’s not a lot of dialogue in the film. You give a performance that could be from a silent film.
It was kind of running joke throughout the film because in the script there was dialogue and we’d run through the lines in the morning, and there were long monologues, and Malgo [Szumowska] would come and say, “No get rid of it! I don’t like it.” By the end we didn’t bother learning them.
Did the bad Irish weather during the shoot add to your performance?
Definitely. When Selah is shivering, that is completely genuine. It added tension to the film. And because there were so many of us women and girls, we were actually forced together — we didn’t have a choice — we were all so close we were genuinely a family because we had to stick together and keep warm. It definitely worked out for the better. The cast and crew were all very happy. While very difficult, they were very happy with what ended up on the screen.
Was there a certain level of trust with a woman director on this women’s story?
I definitely had massive trust in Malga. We hit it off straight away when we met each other.
But I don’t think that trust was because she was a woman, because I’ve been lucky enough to work with enough directors — male or female — that I’ve always had that kind of trust with them.
Maybe it’s because I’ve been lucky to work with male directors that I also had trust in so I don’t see the difference. I just see them as a director.
Talk about your relationship with the director.
Malga is a different kind of director. She’s so straightforward, it’s actually kind of refreshing. If she didn’t like the way we were doing something, she would say, “I don’t like it. Do something else,” which at first, you’re like, “oh, OK.” When you get used to it [her method] is quite helpful. What a lot of directors do is try and be nice and skirt around what they’re actually trying to say, which takes a lot more time, instead of Malga actually saying, “I don’t like it. Do something different.” It’s refreshing.
I’ve been reading different scripts. [I’m doing] something that’s set during the war. It’s based around a bunch of girls growing up at that time. But I can’t say anything more.