Eliza Clark’s 2020 debut novel Boy Parts, a brutal artworld satire-cum-thriller, is a publishing phenomenon. It has sold more than 30,000 copies in the UK and gained a huge following on TikTok, with readers posting their favourite quotes. Now it’s been turned into a stage play, adapted by Gillian Greer and starring Aimée Kelly as the wildly unreliable narrator.

Greer first encountered the novel through the audiobook, which is narrated by Clark. She was immediately struck by the theatrical potential of the story about an artist who takes explicit pictures of young men. “Irina is a frightening, delicious character who I wanted to spend more time with,” says Greer, who has distilled the book into a monologue.

Majestically self-absorbed, frequently cruel and aggressively transgressive, Irina does some appalling things. Although she violates and abuses the subjects of her photographs and does not care about issues of consent, she is not invulnerable and is often chaotically self-destructive. It is these contradictions that make her so exciting for Greer.

“I hate using the term likability,” says director Sara Joyce, who doesn’t think the book is asking you to like or dislike Irina. “It’s inviting you to engage in a more experiential way.” There’s something dangerous about the character and the way that she approaches the world, Joyce thinks.

For Greer, a key part of the novel’s appeal is the way Irina’s volatility and her photography are intertwined. “She wants her art to be evidence of her power, evidence of her threat. Her work is a way of proving to the world what she is capable of doing.” However, says Greer, Clark also shows how easily her work gets swallowed by “the machine of capitalism and the patriarchy of the art world”.

“No matter how good she may be,” adds Greer, “she just can’t outrun other people’s perceptions of her.” For Joyce, Irina is “somebody doing absolutely everything they can to be taken seriously”; her frustrations in this respect are relatable, even as her behaviour becomes increasingly unhinged. Irina’s expression of both her sexual and creative desire stands out: “We don’t often see or encounter women who feel free to express that they like sex in this way,” Joyce says.

Still at a relatively early stage in the creative process, the four women – Greer, Joyce, Kelly and Clark – are figuring things out. However, the director is certain that the production won’t feature erotic photography. “What our minds can do is a lot more interesting,” Joyce says. She is keen to bring out the psychological thriller aspects of the text and has been thinking a lot about Hitchcock. Fittingly, Peter Butler’s set design will evoke a camera lens.

Co-produced by Metal Rabbit, the play will run at Soho theatre, a venue with a history of solo shows about “messy” female protagonists, such as Phoebe Waller-Bridge’s Fleabag and Liz Kingsman’s One-Woman Show. Greer feels that Boy Parts will be a way of “moving the dial forwards”.

Throughout the book, the sense of what is real becomes increasingly blurred. “We’ve deliberately tried to honour that ambiguity,” says Greer. Joyce hopes audiences will leave with different ideas of what Irina is or isn’t capable of doing: “I’d like it if they argued about that afterwards.”

Kelly, who recently starred opposite Idris Elba in the TV series Hijack, says that she has found “a tremendous amount to unpack” with Irina. Despite the darkness, she was drawn to the character, in part because there is still a relative dearth of stories about young women from the north-east of England. When she first read the novel, Kelly remembers being struck by how well it captured the experience of being fresh out of university.

“It is interesting to me how she perceives herself and how she perceives others perceiving her,” Kelly adds. In so many encounters Irina has, she has to shapeshift. “A major ingredient in the story is her gaze and the gaze in general,” which is something they are exploring in the rehearsal process, mindful of the fact that performing the monologue alone to an audience brings an extra dimension. On stage, she adds, “there’s nowhere to hide”.

• Boy Parts is at Soho theatre, London, 18 October-25 November