Distributors ought to have snapped up The Miseducation of Cameron Post. Adapted from a hugely popular young adult novel, and with a big name star in the shape of Chloe Grace Moretz and glowing reviews, the film seemed destined for box office success when it premiered at Sundance at the start of the year. And yet, even after it went home with the coveted Grand Jury Prize, it took months to get sold. Moretz thinks she knows why.

“The powers that be are afraid of taking chances,” says the 21-year-old, sitting in a London hotel suite, her feet plonked on the table in front of her. “I think people can really connect to this film across the board —it’s a John Hughes film in a lot of ways… it’s just gay people are the leads, instead of straight people.” Because of that, she says, “We were told that our movie would be hard to market”.

For Moretz, though, it was part of the reason she took the role — her return to acting after a year and a half break — in the first place. After appearing in more than 40 films before she was legally able to drink, including Kick Ass, (500) Days of Summer, Carrie and The Equalizer, she had taken a step away from movies “to figure out exactly what connected to me, and said something about who I am”.

The Miseducation of Cameron Post, the story of a teenage girl sent to a gay conversion centre —God’s Promise — after being caught having sex with her best friend, was the first to do that.

It was the film’s director, Desiree Akhavan, to whom Moretz was initially drawn. When Akhavan’s semiautobiographical debut came out in 2015, she was dubbed “an Iranian, bisexual Lena Dunham” —a somewhat reductive comparison, but one that spoke to their shared ability to meld humour and pathos in almost uncomfortable ways.

“Her use of levity in the darkness speaks volumes to the queer lens,” says Moretz. “Having two gay brothers, and growing up a part of the community, it’s always been obvious to me the amount of comedy that you use to get over the bigotry and obstacles you’re faced with. You use levity to find those silver linings in your darkest times.”

Moretz’s answers are often like this — earnest, articulate, vaguely pre rehearsed. She’s been doing interviews for over a decade, and has honed a steely, professional sort of friendliness; the sort that doesn’t feel false, exactly, but leaves you with no delusion that she’ll remember you five minutes after you’ve left her orbit.

Still, her enthusiasm for Cameron Post is evident, and now it has finally found distribution, the film deserves to be seen.It is warm and affecting, treating a deeply troubling subject matter with the sensitivity it deserves while exposing the absurdity at the heart of it. When Cameron meets Dr Lydia March (Jennifer Ehle), the quietly malignant founder of God’s Promise, she says she can call her Cam. “Cameron’s already a masculine name,” shoots back March. “To abbreviate it to something even less feminine only exacerbates your gender confusion.”

As it turns out, refusing to shorten someone’s name isn’t enough to shift their nature — and forcing repressed queer teenagers to share rooms isn’t quite the bright idea it might have seemed either. One night, Cameron has a brief, intense fumble with her female roommate. Filming it with a team of women behind the camera —a rare experience —made a “massive difference” to Moretz.

“With pretty much everyone on the set being a woman, I wasn’t told what I had to get done in the scene; they trusted me to do my job, and Ashley (Connor, the director of photography) shot it not focusing on the ass and the bodies, just the beauty and reality of it.”

In most of the sex scenes, in fact, the people involved are fully clothed. “Exactly! And it’s still really intimate and more emotionally provoking than most I’ve seen on screen ever, but that’s because of the female lens.”

It made a palpable difference too, says Moretz that the film was made by LGBTQ people. “It’s a queer movie, by queer people, for queer people.” But what about Moretz herself? Though earlier she told me she was as an “advocate and an ally and an activist for the LGBTQ community”, she stopped short of professing to be a member. She’s also had a high-profile, on-again off-again relationship with David Beckham’s son, Brooklyn.

A recent article on queer erasure in cinema name-checked Cameron Post, alongside a handful of other prominent films, as an example of a straight actor playing a gay lead role. “Oh really?” says Moretz, her tone tinged with irritation. I start to recite her costar Sasha Lane’s response — that Akhavan “didn’t feel the need /right to ask a 19-year-old who she f***s”, —but Moretz interjects. “Well I think what’s important is don’t assume anyone’s sexuality,” she says. “I mean, across the board,” she begins to chuckle nervously, “don’t assume.”

“I think it comes down to the line that’s in the movie,” she continues. “She says, ‘I don’t see myself as a homosexual, I don’t see myself as anything.’ These are all societal pressures that we’re being labelled as. We’re all human, trying to be with the people that we fall in love with, and be the best person that we can be. But don’t assume people’s sexualities. And don’t project your own issues onto them. Why don’t we let people be who they wanna be?”

The issue, she insists, is not the same as white actors being cast in roles intended for people of colour. “You can’t compare it,” she says. “You (also) can’t compare it to trans actors playing trans characters. I think… there are different levels. And people can… you know…” For the first time today, she seems a little thrown. “Just don’t assume people’s sexuality,” she repeats again. “It’s unfair.”

Ultimately, Moretz believes there are more important conversations to be had around Cameron Post than the minutiae of her own sexual identity. Though the film is set in 1993, practising gay conversion therapy on children is still legal in 36 states in the US. “If you put the film into the context of 2018, nothing’s changed,” she says, “Especially in the world of conversion therapy.”

In preparation for the role, she met with five survivors of the practice. “The first thing that hit me,” she says, “was the modernity of it. They were in their mid-twenties.” What did she ask them?

“I wanted to know whether or not they actually wanted it to work, or whether they knew from the beginning that it’s just complete hypocrisy. Across the board, they said the people pushing them the most were themselves. They badly wanted it to work, as they wanted their family to love them.”

Moretz is clearly, and justifiably, very proud of being involved with the film. Combining her passion for social justice with good quality art, she says, “Is like a dream come true for me. I can have a hidden message, and people are also entertained? That’s all I need.”

The independent