As for the Jane Austen homage, says Lethem, well, he had better re-read Emma soon because it's decades since he did so and he's about to go on the road for the American publication of his new comic novel. He certainly admires Austen, he says, but he can't quite get his head around the "echoes" of her work. An influence? He was unaware of it until his editor pointed it out to him.
In fact, he says, when we meet in the Brooklyn brownstone where he shares an apartment with his third wife, documentary film-maker Amy Barnett, if You Don't Love Me Yet owes a debt to any other writer, it is to Iris Murdoch, of whose early fiction he is a devoted fan.
Murdoch, his British editor told him, is unfashionable in lit-crit circles nowadays, so they would prefer not to mention her influence on him. Austen, though, like the poor, is always with us.
"I wanted to write about an indie rock band in Los Angeles," says the author of two collections of short stories, a huge body of essays and non-fiction, and six literary novels, including the savagely beautiful bestseller Motherless Brooklyn.
That won Lethem, 43, both plaudits and prizes, and has been translated into 15 languages. The film rights were bought by Edward Norton, who is writing the screenplay and has plans to star as the brilliant central character - a tapping, twitching private eye suffering from Tourette's Syndrome.
Lethem's last novel, The Fortress of Solitude, an epic, pop-culture infused (the title refers to Superman's Arctic refuge) roman--clef about the unlikely friendship between two motherless boys, one white, the other black, also became an international bestseller, with American critics describing the writer - warning: another comparison - as "the 21st-century Don DeLillo".
With You Don't Love Me Yet, Lethem explores the world of the romantic comedy filtered through a lively intellect and with knowing nods to LA noir.
The author, who bears more than a passing resemblance to the actor Ben Stiller and who speaks in perfectly punctuated sentences, indeed, whole paragraphs, says he asked himself how Murdoch would have handled a satirical tale of drifting, clueless rock musicians.
Throw into the mix allegations of plagiarism, usurpation, and a kidnapped, deeply depressed kangaroo, then add some complicated and sophisticated sexual shenanigans and philosophical musings, and you have another virtuoso performance from a daring writer.
In previous books, Lethem has often dabbled in genre-bending: his first novel, 1994's Gun, With Occasional Music, mixes dystopian science fiction with noir mystery, while 1997's She Climbed Across the Table turns a physicist who is curious about black holes into a post-modern Alice in Wonderland, and 1998's Girl in Landscape, set on another planet, is, he says, "a Western with aliens".
"The autobiographical novel is yet another genre," says Lethem, who prepared for The Fortress of Solitude by having long conversations with family and friends about times past. "I borrowed a lot of their tales, their souls," he confides.
He wanted to reply to other autobiographical fictions he had loved, such as Somerset Maugham's Of Human Bondage, and was also keen to write about his own rites of passage, an exercise he repeats in You Don't Love Me Yet - a homage to the potency of popular music. Lethem is mad on rock, as well as soul, punk, funk and rap, and has written extensively about them.
Indeed, the novel, which has received mixed reviews - ranging from "preposterous but fun" (New York Times) to "self-conscious, referential cleverness" (Los Angeles Times) - was launched in the United States with indie bands performing competing versions of Monster Eyes, the fictional song that leads to the unnamed You Don't Love Me Yet band's fleeting celebrity at an "art" happening.
The band breaks up when it emerges that Lucinda, the bass player and the novel's central character, has appropriated words and phrases from someone else and turned them into lyrics. Those fragments become catchy, even powerful, songs. The question of plagiarism fascinates Lethem, who wrote a recent magazine essay, entitled "The Ecstacy of Influence", in defence of artistic plagiarism.
But it's the mysterious songwriting process that really exercises Lethem's imagination.
Capturing the moment in fiction was a challenge. "Of course it's hard for prose fiction to be like a pop single," he admits. "It's almost impossible but I really wanted to try." So, imagining the birth of Monster Eyes during a rehearsal, he writes:
The sound was sprung, uncanny, pre-verbal, the bass and drum the rudiment of life itself, argument and taunt, and each turn of the figure a kiss-off until the notes began again. Who needed words? Who needed guitars -- those preening whiners. Lucinda then sings snatches of a lyric: "Get Out Of Range Of My Monster Eyes"... and a song takes shape, to the band's collective astonishment.
A "1970s kid", Lethem and his siblings - he has a younger brother, Blake, a noted graffiti artist, and sister Mara, a photographer and writer - grew up listening to rock music. They had a "thrilling" childhood. He recalls seeing Star Wars 21 times and reading everything by Philip K Dick, whom he would love to meet in a bar in heaven one day. They were raised by their father, the reclusive avant-garde artist Richard Brown Lethem, and their late mother, Judith.
They grew up in a chaotic commune full of artists and sprawling life. The hippie-ish Judith was a dedicated political activist and was arrested on the steps of the US Capitol at an anti-Vietnam War rally. She died from brain cancer when Lethem was 13.
Her death haunts him, he says, although he believes he's inherited the life of the committed artist from his father, who carried on painting while grafting hard as a carpenter and house restorer in order to keep the family together.
"My books all have this giant, howling missing centre - language has disappeared, or someone has vanished, or memory has gone," sighs Lethem. "I'm for ever writing around a void - I guess I don't have to explain to you why that is."
Each of his novels, antic as they may sometimes be, is fuelled by loss, he wrote in The Disappointment Artist, a collection of his autobiographical essays. "I find myself speaking about my mother's death everywhere I go in this world."
Lethem grew up on Dean Street, in Brooklyn, in the shabbily hip Boerum Hill, where Isaac Asimov once lived and where Malcolm X's family was kept in a safe house, which Lethem took me to see the last time we met.
Today, he lives only a few blocks from his childhood home and not far away from his old primary school, where he recalls the air crackling with racially tinged tension. This area is the setting for both The Fortress of Solitude and Motherless Brooklyn.
You Don't Love Me Yet is, however, entirely set in LA, a place he has always been curious about and where he spent time researching, ending in a long, unplanned visit to the zoo, "a piece of serendipity," since it became the backbone of the book. "I can't imagine the book without the zoo, so weirdly it became this metonym for Los Angeles itself.
"It was time to leave Brooklyn in a literary sense anyway - between Motherless Brooklyn and Fortress of Solitude I had really plumbed childhood in Brooklyn. I really needed to defy all that stuff about place and memory," he says.
Nonetheless, his heart clearly belongs to New York's mad, bad and dangerous bastard offspring, with its mean streets, graffiti-pocked walls and blighted brownstones, which are rapidly being gentrified. Lethem no longer recognises the Brooklyn in which he grew up, although he says he still sees the past - that foreign country - on every stoop and every slate sidewalk.
He and Barrett have recently bought a farmhouse in Maine, near where his father lives, in a town called Berwick. His father is still painting. Also a gifted artist, Lethem took art seriously for a while. He went to the arts-oriented Bennington College in Vermont on an art scholarship, but dropped out to work on a novel.
"The art world just didn't attract me at all," he says. "The writing world did. And that was always the giveaway - writers are much more interesting to me than artists.
"Losing myself in the art of geniuses - in a book. That's what make me happiest."
• You Don't Love Me Yet by Jonathan Lethem is published by Faber and Faber, priced 10.99.
Jonathan Lethem on...
Sense of place: In previous books, I became the bearer of communal memory for a Brooklyn neighbourhood and there was an enormous sense of wanting to get the details exactly right. But I felt I'd a licence to "fake it" with the Los Angeles setting of You Don't Love Me Yet, because I don't know it well. And I really wanted to be irresponsible, to get back to the sense of play in fiction - to put on a play. LA is my proscenium arch.
Genre switching: I've made a great effort to try different kinds of things, expressing my adulation for various kinds of American popular culture and pop-culture forms - rock'n'roll and comic books, science-fiction, detective stories and film, especially film noir and the Western. What unites my books, I think, is the way they all try to express passion for a genre but also a refusal to settle down and be simply one kind of thing.
Influences: Charles Dickens has been the most enormous influence on me. He's one of the reasons I wanted to become a writer. The Fortress of Solitude, for instance, has a Miss Havisham figure, a Magwitch and, of course, the semi-autobiographical character of Dylan is my Pip. But then I also love Philip K Dick and Paula Fox, Donald Barthelme and Angela Carter, and Lewis Carroll and LP Hartley...