Catherine Called Birdy has made its way from the Toronto International Film Festival to a theatrical run, playing in select theaters before premiering on Prime Video on October 7. Partly historical fiction, the teen comedy follows a 13th-century girl with a rather modern mentality. Bella Ramsey (who first wowed audiences as Lyanna Mormont in Game of Thrones) plays Lady Catherine, who wishes only to be called "Birdy" and avoid marriage at all costs.

Birdy's father Rollo (Andrew Scott, whose villainous turn in BBC's Sherlock has made him a fan favorite) must marry his only daughter as a means of earning money, however, and therein lies the central conflict of Catherine Called Birdy. When the young heroine despairs of her parents ever understanding her desire for freedom, she turns to her Uncle George (Joe Alwyn, Conversations With Friends), whom she venerates. But the young lass soon comes to realize that even he isn't as perfect as she believed, and she must face up to her life on her own. Lena Dunham directed the film and wrote the screenplay, which is based on the children's book by Karen Cushman.

Related: Catherine Called Birdy Review: Dunham's Medieval Comedy Is Lighthearted Fun

Screen Rant spoke to Alwyn and Scott about how each of their characters relates to Birdy, as well as why Dunham's acting background helped her direct Catherine Called Birdy.

Andrew Scott & Joe Alwyn Talk Catherine Called Birdy

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Joe Alwyn and Bella Ramsey in Catherine Called Birdy

Screen Rant: Lord Rollo obviously loves his daughter, but they have a quite an antagonistic relationship at times. Can you talk about how he views Birdy, and what it was like playing off Bella?

Andrew Scott: Yeah, I think that's absolutely true. I think they have an antagonistic relationship, and I feel that he's almost intimidated by how independent and willful she is. I think he sort of adores her, but he has got so many demons himself.

I don't think he's very secure in his own masculinity, in the sense that he hasn't come from money himself. He's spent a lot of money, and he's a little bit feckless; he's loose, and he's lost a little bit in life. And so, a lot of his dignity lies in the fact that he has to provide for his family, so he doesn't have a lot of dignity because he's not providing for his family. The antagonism comes when he feels like he's found a solution, which is that he's going to marry her off to some rich dudes that come to town, and she is not having any of it. The challenge was to try and show that antagonism, but also to show in some ways that they are cut from the same cloth.

What was wonderful working with Bella was that she was so brilliant, as she was in no way intimidated by the character. And we had a lot of improvisational stuff to do and it was so much fun. By the end, I felt like I really understood Birdy and Rollo, but I also really got to know and admire the whirlwind that is Bella Ramsey, because she carried the whole film on her shoulders.

Uncle George, on the other hand, has a much warmer dynamic with Birdy. She obviously idolizes him a lot, much more so than he perhaps idealizes himself and his own deeds. What is that dynamic like for you?

Joe Alwyn: That's just it. It's that kind of early teen hero-worshipping of someone who you know, somebody you have a crush on someone, or a family friend. Whoever it might be, you think they're just the be-all, end-all knight in shining armor.

And then at some point, there's that very relatable feeling of realizing that heartbreak of how they've actually they made mistakes, and they're messy, and they can be ugly. They're just normal as well, which I think is such a universal [feeling]. Certainly I can remember instances like that. Be with whoever—friends or parents, you see someone make mistakes or not be there for you when you thought they should have been, and you realize they're not this gleaming thing that you once thought they were.

Everyone knows Lena Dunham as an actress and a creative mind, but how do you think her experience in acting has affected her processes as a director?

Andrew Scott: That's such a good question, and I think it's really true. Because sometimes when you're working in movies, the director can forget that it's a pretty vulnerable thing to do. Particularly if you're asked to improvise, or you come up with new stuff; you're doing your take, and the director is far away. And then they feel like they've got what they want, and then they move on. You think, "Oh, was that good?"

Whereas Lena is incredibly validating, and she tells you exactly what she liked about it, what she didn't like about it, or where it should go. She's just completely enthusiastic and loving and kind, because I think she understands that it can be a difficult thing to do. I feel she's very sensitive to how scared you might be.

Joe Alwyn: Yeah, she really takes care of you and makes you feel at ease. [She's] is incredibly positive and wants you to play around as well.

Andrew Scott: Because I think that's all you want. If you have to play a part, you have to have a playful atmosphere. If you feel like, "Oh my God, this is intimidating. I'm intimidated here," it just doesn't get the best out of the actors. And so, she's very warm.

Joe Alwyn: I think so, yes. So much of it is just about creating an environment where you can relax.

About Catherine Called Birdy

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Andrew Scott and Bella Ramsey in Catherine Called Birdy

A teenage girl in Medieval England navigates life and tries to avoid the arranged marriages her father maps out for her.

Check out our interview with Bella Ramsey and Lena Dunham as well.

Catherine Called Birdy is currently playing in select theaters, and will be streaming on Prime Video beginning October 7.