The rock documentary “20,000 Days on Earth” follows singer-songwriter Nick Cave as he visits a therapist, records an album and drives around with friends. (Drafthouse Films)

An unconventional and, at times, profoundly beautiful hybrid of fly-on-the-wall documentary and drama, the film “20,000 Days on Earth” stars the singer-songwriter Nick Cave essentially playing a character called “Nick Cave.” Shaped around a day in the life of a lightly fictionalized version of himself, the film is presented as taking place on Cave’s 20,000th day of existence, at least according to Cave’s poetic voice-over narration, which opens and closes the film, giving it a lovely, literary gloss.

That 20,000-day timeline would place the action of the film just few months shy of the Australian-born rocker’s 55th birthday in 2012. Opening with a shot of Cave waking up in his bed in his adopted hometown of Brighton, England, the movie segues to scenes of its subject going about his business, which includes taking stock of his life with a psychotherapist.

Played by therapist Darian Leader — who is not Cave’s actual therapist — the character is more interviewer than analyst. Leader’s conversation with Cave plays more like a talk show interview — albeit a particularly reflective one — than therapy. It also sets the tone for the oddball little film from first-time feature filmmakers Iain Forsyth and Jane Pollard, who stage additional phony chats between Cage and other people. An entire series of dreamlike conversations take place between Cave, driving his car, and various friends and collaborators from his past, including actor Ray Winstone, musician Blixa Bargeld and pop singer Kylie Minogue, who had an unexpected hit with Cave with their 1996 duet “Where the Wild Roses Grow.”

But the movie “20,000 Days on Earth” isn’t so much a portrait of the artist as a middle-aged man, looking back on his life, as it is a meditation on the art of storytelling.

Cave is, after all, a kind of surreal raconteur in song. The movie, in part, is a making-of film, allowing us to eavesdrop on Cave’s creative process as he works on his 2013 album “Push the Sky Away.” Those scenes — set in Cave’s studio and over a meal in the kitchen of his frequent collaborator Warren Ellis — are the most naturalistic and artifice-free passages in the film. It’s a real treat to be offered insight into the ordinarily camera-shy Cave’s songwriting, which is notable not just for its allusive eccentricity, but for a tone that is at once passionate and cerebral.

Though emphatically not a concert documentary, the film features a couple of electrifying live performances near the end. For the uninitiated, it offers a demonstration of what is so mesmerizing about this performer, who is by, his own description, “a kind of ostentatious bastard.”

Because the film features scenes of Cave looking through old photographs and sharing anecdotes about his childhood and his career with his band, the Bad Seeds, “20,000 Days on Earth” is, in some ways, a traditional artist’s profile. One nevertheless gets the sense that the “Nick Cave” we’re presented with on camera is pretty much a construct.

That doesn’t mean that he, or the film, is fake. Far from it. “20,000 Days on Earth” gets at a larger point: Art tells the truth by lying. The film closes with Cave musing aloud about the role of art as a “shimmering space where imagination and reality intersect.”

It’s a place, Cave suggests — whether on film, on CD or on stage — where life isn’t less real, but more so.

★ ★ ★ ½

Unrated. At the AFI Silver Theatre and the Angelika Pop-Up at Union Market. Contains obscenity, drug references and nudity. 97 minutes.