In Cillian Murphy’s new film Steve, the 48-year-old Irish actor plays the title character with a ferocious intensity, instilling fiery emotions into nearly every scene. Yet it’s the 31-year-old British rapper Little Simz who gets the final word. Or, more specifically, the final 350 words. An actor in the poignant drama, too, Little Simz (she’s credited under her real name, Simbi Ajikawo) has an electrifying song called “Don’t Leave Too Soon” that plays over the end credits. “Your pain, I feel it too,” she whispers over a raucous drum-and-bass instrumental.

The words are apt for Steve, a haunting feature directed by Tim Mielants and adapted from Max Porter from his own novel Shy. It’s 1996, and a reform school is facing disrepair and possible closure amidst Tory cuts. Steve, an overworked teacher with a hidden substance abuse problem, cares deeply about the students; embodied by Murphy like an overgrown child, Steve playfully bickers with his pupils, rather than patronising them. One troubled teen, Shy (Jay Lycurgo), forms an especially close connection with the educator, the pair recognising an underlying sadness in each other.

New at the school is Shola, a meek, introverted teacher played by Little Simz. Her freshness is juxtaposed with Steve’s exhaustion; when he’s caught drinking booze during the day, other staff members are more surprised he’s trying to be discreet. But ultimately, what drives the adults is the students. When they’re not unruly and prone to smashing up the building, the kids are joyous, funny, and acting out what the teachers wish they were permitted to do. During the 24 hours that Steve unfolds, a visiting MP addresses the students and offers to answer questions; in a faux-professional manner, one asks why he’s such a “cunt”.

One afternoon in London, we sat down with Cillian Murphy and Little Simz to discuss Steve, the similarities between rapping and acting, and shooting a key scene when you know you’re playing Glastonbury the next day.

In acting, you’re credited as Simbi Ajikawo, but in music it’s Little Simz. What should I call you for this interview?

Little Simz: Whatever rolls off the tongue, man.

And Cillian, you don’t have a rapper name, do you?

Cillian Murphy: No [laughs].

Little Simz: He’s DJ Cill, now.

“Don’t Leave Too Soon” is such a beautiful song to have over the end credits. Did you record it after shooting the film?

Little Simz: I watched an early cut of the film, and was blown – blown! – away by the performances, man, and how raw they were. That inspired where I wanted to go with the songwriting, the sounds, and the juxtapositions. I love things that should work but kind of don’t work. Strings with jungle just felt like: ‘How? But if we can get it right, it’d be great.’ It’s the beauty and the pain. It’s those two things put together.

I really like it when you whisper the lyrics.

Little Simz: Whispering can either be really dark and sinister, or comforting. The duality was what I was trying to showcase.

Cillian, did you have any feedback for the song?

Cillian Murphy: No. Never in our wildest dreams did we imagine that we could have a Little Simz track to close the film – genuinely. And also a tune like that? It sums up the whole film, because, like you were saying, it has a tenderness, but it has an aggression to the beat. That’s what it feels like to be at that school. You’ve got moments of real connection, and then you have all this potential for violence at every corner.

Is the song from Steve’s perspective? Because of how it refers to seeing the rocks in the bag.

Little Simz: It’s kind of me being a fly on the wall, seeing what these two characters [Steve and Shy] are going through, and talking to them, without them knowing I can see them.

A lot of musicians are fantastic actors. It’s another side of the coin. A lot of acting is musical. That scene that we have at the end of the day, you feel the rhythms

Cillian, you’re a producer, so you brought Little Simz onto the film?

Cillian Murphy: When Max wrote the script, he said, ‘Imagine if we could get Little Simz to play Shola. That would be fucking amazing.’ I used to do this radio gig on 6 Music, and I’d always play her music. I’m a massive fan, and I’d seen your work on Top Boy. A lot of musicians are fantastic actors. It’s another side of the coin. A lot of acting is musical. That scene that we have at the end of the day, you feel the rhythms.

Simz, I imagine you get offered a lot but are quite picky.

Little Simz: Not as much as you think, mate [laughs]. With music and film, it’s all just storytelling. My personal stuff is pulling from my real-life experiences. With something like this, it’s being part of a wider story.

In that scene at the end of the day, your characters’ faces are radiating these contrasting energies. Both of your eyes are doing different things. Cillian, the camera even zooms in on your eyes.

Cillian Murphy: We shot everything in order. By the time we got around to shooting that scene, we’d got to know each other a bit. [You’re not] acting familiarity. It’s my favourite scene of the film because they’re not saying what they’re feeling. They’re talking around what they’re feeling. A lot of this film is about people not being able to reach each other.

Little Simz: Tim helped guide things. It’s what I love about acting. It feels like there’s space to be an artist and to create. With my character, I was given what was on the page, but I was able to create her as well, while still being true to what’s on the page.

I interviewed Tim for Patrick a few years ago, which is a very different film.

Cillian Murphy: This is my third project with Tim, and, if I could, I’d work with him forever. He cares about actors.

I read the production had to be scheduled around Glastonbury. So, Simz, the scene where you and Cillian are both in the classroom – what’s the gap between filming that, and you being on the Pyramid Stage?

Little Simz: It was the next day.

Cillian Murphy: No! What, after that scene?

Little Simz: Yeah.

Cillian Murphy: Shut up! Oh my God! [laughs] You’re so casual about it.

How do you not get distracted by playing Glastonbury the next day? If I was going to Glastonbury as an audience member the next day, that alone would stress me out.

Cillian Murphy: Me too [laughs].

Little Simz: I was very well-supported by the production on Steve, just making sure I had the headroom to focus on that, and my team made sure that when I’m on set they’re not stressing me out with Glasto stuff.

Will you do the song from Steve live? It’s quite melancholic.

Little Simz: I want to figure out a way. It’d be beautiful to do it with an orchestra, with that drum and bass.

Max said he set the film in 1996 to show the damage a Tory government would have on a school like Stanton Wood. Is that something for a 2025 audience to think about as well?

Cillian Murphy: What I like about the work is that it’s definitely provoking you. The film is considered a period film because it takes place in the 90s. It’s 30 years ago. But yet we’re still confronted by these problems day in, day out. If you shut down places like alternative education or libraries or youth clubs – where are these kids going to go? They become statistics and problems. And then 30 years later, you get more issues.

Just look at the film, and ask yourself the questions. I don’t think the film is trying to provide answers, but it’s definitely trying to get people to have a conversation.

Steve is out now in select cinemas, and streams on Netflix from October 3