There is something unnerving about sitting opposite Olivia Cooke and Anya Taylor-Joy.
Perhaps it's because the last time they were sitting this close together they were plotting a murder.
Not in real life, it should be pointed out, but in their new jet-black comic thriller Thoroughbreds, in which they play bored rich schoolgirls roaming round a Connecticut mansion planning to kill someone.
But that unease quickly melts away.
"I am not going to lie, I considered coming down in my dressing gown. I was like 'screw it'. The best thing about hotels is always the bath robes," Taylor-Joy jokes.
Not so sinister after all.
But in Thoroughbreds, the directorial debut for playwright Cory Finley, she plays the coolly manipulative Lily, who is growing increasingly sick of her loathsome stepdad Mark and his incessant use of a rowing machine.
When she reignites a childhood friendship with Cooke's troubled Amanda, who has become notorious in their social circles for an incident involving a horse, the duo start to hatch a plan to get rid of him, which starts off as bravado to impress each other but quickly turns serious.
"When I first read it, I was absolutely blown away and it was the only thing I could think of," Taylor-Joy says, "and Olivia was actually already attached and I really wanted to work with her."
"I think these two women are manipulating each other through dialogue throughout the entirety of the movie and everyone has got an ulterior motive and nothing is what it seems. That just seems so interesting to play, especially with another young woman. It felt like it was too good to give up.
"I nearly chased Cory out of a hotel room until he told me I had the part.
"I think we all know someone like Lily, where the veneer is so thick and so polished but underneath is just this crazy lunatic."
Cooke (24) nods in agreement. "The characters are so lush. He's written it incredibly well because Cory is just a master observationalist.
"I thought he was a woman when I first read the script because I don't know a guy that can write girls like that.
"And he was 27 when we shot the film! He's just incredible."
Taylor-Joy (21), who has already starred in The Witch and Split, found something so disturbing about the character that it stopped her from her usual practice of swiping a memento from the set.
"I spent the whole movie defending Lily to people on set who were just like, 'God she's so awful, look what she's just done'," she says.
"And I was like, 'You can't talk about my character that way, I'm her right now. I have to be able to defend the things that she's doing.'
"But I keep articles of clothing from each of my characters because I really love them and for Lily I just had to leave everything there, I couldn't carry it with me anymore.
"Actually watching the film is quite hard because I just see her and I'm like, 'Ooooh, you're so hurtful'."
That did not stop her obsessing about the details of her character's meticulous appearance throughout the shoot though.
"I remember having a conversation with the hair stylist about her trying to emulate these old different movie stars and going through her phases and trying to get to a place where she actually feels like herself. I've never had hair like that and it does make such a drastic difference to the way you hold yourself and the way you are.
"You go in in the morning, usually in sweatpants and you're feeling a bit like, 'Oh my God, where is the coffee?' and then throughout an hour you just get transformed into somebody different."
The film was shot on location in the palatial Oaks estate in Cohasset, Massachusetts, which was chosen by Finley to emulate the creepy hotel in Stanley Kubrick's The Shining.
Staying near the remote waterfront house, with its own pool, dock and tennis courts, gave the young actresses ample time to spend together.
"We were living five minutes away from the house and on top of each other so we just walked to work every day," Taylor-Joy says.
"And then in the house we didn't have trailers or anything like that, we were all just like living in these different rooms in this crazy house.
"The whole unit of the film just became a family so we were a well-oiled machine because we shot really quickly even though the scenes are complicated.
"We would just go in and you had to be completely on it because it was going to move at that pace. We just knuckled down and did it."
Reminiscing about the shoot, Cooke adds: "It felt quite intense and it was the most bizarre house as well.
"It was like a hoarder's paradise. They toned it down and made it look quite lovely."
Taylor-Joy laughs at the memory. "We toned down the crazy of the house, that house was madder.
"The grounds were just huge so whenever you weren't shooting you could mosey about. My favourite part of it was a swing set outside.
"I scared the bejesus out of Olivia one night because I was wearing a white dress as I was swinging on this thing and they all thought I was a ghost."
Cooke, the star of Me And Earl And The Dying Girl, as well as the latest Steven Spielberg blockbuster Ready Player One, chuckles mischievously. "There was also a sexy swing that I found in the house in the weird closet."
Taylor-Joy's mouth falls open. "Did I not tell you?" Cooke exclaims."I will tell you later!"
I'm not even out of the room before they start to whisper conspiratorially. That unnerving feeling just came back.
Thoroughbreds is in cinemas now