Rachel Cusk is in a sunlit bedroom of her home on the west coast of France, talking about her new novel. She wasn’t planning on having this conversation about the novel, “Life of M,” but other people have had a lot to say — about whether “M” is actually Natalie Portman, and whether, by writing about an actor who so closely resembles a real celebrity, Cusk has committed some kind of artistic betrayal.

Now Cusk has logged on to a video call to explain, even though she’d rather not be explaining.

Cusk seems bewildered, and a bit distressed, to find herself caught in the harsh spotlight of fame and the kind of tabloid feeding frenzy she evokes in the novel, which features an author who writes about a famous actress.

“It’s very stressful, the thought of these things happening,” she said of the swirl of gossip surrounding the book. “It’s taking the novel that I’ve created into almost a sort of courtroom or a factual fight,” she added.

“What I’ve done belongs much more in a world in which fame, and these people who are so known and yet so unknown, is a part of contemporary consciousness,” she said. “And if my job is not to go into unexplored areas of contemporary consciousness, then I don’t know what it is.”

“Life of M” — which raises uncomfortable questions about the nature of fame and our celebrity-obsessed, image-driven culture — has been fodder for discussion and speculation for weeks as it approaches its Aug. 25 release.

When advance copies began circulating this summer, the protagonist’s similarity to Portman set off a cascade of rumors about whether Cusk had enacted what some called a “literary assassination” of Portman, depicting her as an empty vessel who lacks an identity beyond her film roles and the public’s perception of her.

Cusk, the author of a dozen novels, including the acclaimed “Outline” trilogy, is known for writing experimental books that blur the boundaries between fiction and real life. “Life of M” takes this project into tricky new territory.

Is “Life of M” autofiction? A perverse form of fan fiction? Or is it simply the latest experiment from Cusk, one of our most provocative, slippery and polarizing writers?

In conversation, Cusk, 59, came across as warm and frank, even when artfully and politely evading questions. She speaks the way she writes, with exacting precision, sometimes veering into abstract, philosophical reflections, as if she were working out the puzzle of existence midsentence.

Over email and in a video call, Cusk — who had initially declined an interview request through her publisher but then decided to talk — seemed determined to maintain a patina of mystery around “Life of M.”

Cusk wouldn’t comment on whether she has had any conversations about the novel with Portman, whom she has met. She also wouldn’t discuss the speculation that Portman dislikes the book, as M does in the story. She insisted that whether M is based on a real celebrity “is not really the point.”

“It’s a work of fiction, and I guess explaining how something is created, because it’s always created out of a total mishmash of real things and invented schemes and personal material — once you start to pull on that thread, it would unravel the whole thing,” she said.

“The book explains itself and defends itself pretty comprehensively,” she continued, “and it’s something I created, so to start to explain it kind of ruins it for me.”

From the very beginning of “Life of M,” readers are on shaky ground. Its narrator is a nameless author who plans to write a closely observed portrait of a celebrity, identified as M. At first, M is on board, but when she reads the work, she tells the writer she’s unhappy with how she is portrayed; the writer is baffled, and tells M, “the character was invented by me.”

Whether or not M resembles Portman is hardly a question. The parallels are specific and numerous. Like Portman, M got her start as a child actor, and later starred in a movie about a ballerina who has a mental breakdown and in a film about a celebrity who survived a school shooting. M, like Portman, is the face of a major brand and appears in ads festooned with flowers. Though the city where M lives is not named, it is recognizably Paris, where Portman and Cusk both live.

Cusk and Portman have crossed paths, and Portman has called Cusk “one of my favorite writers.” The pair had a friendly and thoughtful conversation in 2022 about Cusk’s novel, “Second Place,” which Portman selected for her book club.

Portman’s admiration for Cusk’s work fed into the feverish debate over “Life of M,” prompting an avalanche of social media commentary and articles citing unnamed sources close to Portman who claimed she was displeased with the project. There were breathless headlines like “Is Rachel Cusk’s new novel a ruthless betrayal of Natalie Portman?” (Portman’s representatives declined to comment for this article.)

Cusk seemed surprised that anyone found the subject of the novel scandalous. As she sees it, “famous people enter the public imagination, and though I dislike that phrase, it is part of fame’s deal, and part of its tragedy.” Plenty of movies and novels have featured public figures, she noted, often without stirring much controversy.

In some ways, writing a fictional account of a celebrity’s glamorous but hollow life is a surprising move for a writer as cerebral and iconoclastic as Cusk. “I don’t think anyone could see me as a writer naturally drawn to celebrity culture,” she conceded.

Yet from another angle, fame and its trappings seem like perfect territory for Cusk, who has long been preoccupied with the unstable nature of identity.

When she had the idea for “Life of M” a little more than two years ago, Cusk realized that writing about an actor would allow her to explore the themes of selfhood, artifice and authenticity in a new way.

“I couldn’t believe I’d never had that idea before,” she said.

Imagining her way into the life of a famous person also felt like a kind of escape.

“Perhaps the book was my arrival at that psychological need, a desire to almost pause being myself and to have some vacation from myself, some other place to go,” she said. “It was like, what would it be like to be able to lose yourself or leave yourself, and is that what the celebrity offers?”

Using a famous person as a fictional character was, Cusk said, “a kind of game, and the rules of the game are that the actor and the narrator are both real.”

For Cusk, drawing on details from the life of an actor was a way to anchor the story in the real world, and then, in a sort of narrative rug pull, reveal the layers of artifice that shape our impressions of reality.

When the narrator insists that the vivid account of M’s life was all imagined, it’s “a way of making everything just disappear in a puff of smoke,” Cusk said. If readers are unsure what’s real and what’s made up, that’s partly the point.

“It’s almost like the book that you’ve just read completely explodes and self-destructs at the end,” Cusk said. “I felt that would possibly make a reader reflect on what they’ve just read, in a rather disorienting way.”

Born in Canada in 1967 to British parents, Cusk grew up in Los Angeles and in Britain, where she had a miserable time at a Catholic boarding school and later attended Oxford. She published her first novel, “Saving Agnes,” in 1993, and went on to write 11 more novels and three memoirs, which include her account of the trials and sacrifices of motherhood, and a brutally honest dispatch from the front lines of her divorce. Her memoirs were slammed by some book critics, especially in England, where she was pilloried as a bad mother to her two daughters, and as a narcissist who callously mined the lives of those around her for material.

After the maelstrom unleashed by her divorce memoir, “Aftermath,” Cusk said she had felt paralyzed and unable to write. She became disillusioned with herself as a subject, and resolved to find a new way of writing that sidestepped the problem of subjectivity and authorial identity. That led to her “Outline” trilogy, a series of novels about a Cusk-like writer who rarely expresses her own thoughts or feelings as she acts mostly as a receptacle for the stories of the people she encounters.

The trilogy, which came out between 2014 and 2018, cemented Cusk’s reputation as one of the most formally innovative and stylish writers at work today.

Since 2020, Cusk has lived in Paris with her third husband, the painter Siemon Scamell-Katz. They also spend time in their home in the Charente-Maritime region of France, where they often retreat to work. Cusk’s writing has become even more abstract and experimental in her most recent books, “Second Place” and “Parade,” which feature narrators who are nearly invisible and characters who don’t have names beyond initials.

It’s as though she’s systematically stripping away even the rudimentary elements of narrative. With “Life of M,” Cusk has pushed the idea of an opaque, cipher-like narrator to its near limits. When she began writing it, she struggled for a long time with the book’s structure.

“What was really interesting to me was how difficult the book was to write, and how difficult it was to truly exclude the content of the self with all of its assumptions and its prior knowledge and its associations and perceptions,” she said. “It really had to be letting surfaces speak, so that was much harder to write.”

Early responses from literary critics have been mixed. A review in The New Yorker by Becca Rothfeld called it “Cusk’s weakest novel yet,” and noted that “Cusk has invented a new sort of novel that is nearly unidentifiable as such.” Writing in Slate, the literary critic Laura Miller was more intrigued, describing the novel as a “tricksterish piece of work” that dangles as a lure the idea that we might be reading about a real celebrity.

“Everything in the book leads you to believe it’s a roman à clef — only when you get to the end does she explode all that,” Miller said in an interview. “Then it’s like, what did I just read?”

The writer Sheila Heti, a friend of Cusk’s who read an early draft of “Life of M,” said the controversy that has erupted over M’s resemblance to Portman only proves Cusk’s point about how the public feels entitled to access the inner lives of celebrities, and then imposes false story lines.

“Everyone who is projecting onto Natalie Portman a sense of betrayal over her alleged appearance in the book is in fact enacting the very projection and storytelling that the book is thinking about, and is critiquing as kind of dehumanizing,” she said.

Cusk, who isn’t on social media, has largely kept her distance from the chatter around “Life of M.”

She hopes the questions and critiques will fall away once more people read the novel, and realize how weird and subversive it is.

“To me, the book, it’s a daring book, it’s a strange book, and it isn’t a scandal or a subject for gossip; it’s a strange voyage through territories that are pretty legitimate, that are about the public and the private,” she said.

“I’d like it to be allowed to be the strange confection that it is,” she said. “I don’t think it’s looking for trouble.”