Leonardo DiCaprio and Brad Pitt play a fading action star and his inseparable stunt double in Quentin Tarantino's freewheeling trip through 1969 Tinseltown at the time of the Manson murders.


Quentin Tarantino renews his vows as a devout fanboy, rifling through his formative influences in vintage American B-movies and TV, spaghetti Westerns, martial arts, popular music and an endless assortment of cultural ephemera in Once Upon a Time in Hollywood. In his ninth feature, the writer-director at the same time is having sly fun riffing on his own work, in particular his penchant for gleeful revisionist history. A sizeable audience will doubtless share that enjoyment, even if the two ambling hours of detours, recaps and diversions that precede the standard climactic explosion of graphic violence are virtually plotless.


The central characters — played by returning Tarantino cohorts Leonardo DiCaprio and Brad Pitt in entertainingly loose performances dripping with self-irony and pleasurable chemistry — are faded television cowboy Rick Dalton and his longtime stunt-double Cliff Booth. But since an excess of DUIs cost Rick his license, war hero Cliff is now more of a driver and all-round gofer, doing little actual stunt work, while Rick's planned transition into action movies has failed to catch fire. That his extensively excerpted star vehicles bear some resemblance to Inglourious Basterds and The Hateful Eight makes Rick's gnawing doubts about his career seem almost like an exploration of Tarantino's own creative crisis. Or maybe not.


With richly detailed input from production designer Barbara Ling and beyond-cool retro fashions from costumer Arianne Phillips, Tarantino folds the low-key buddy comedy into a lovingly recreated, almost fetishistic celebration of late '60s Hollywood, infused with color and vitality by cinematographer Robbie Richardson. It's stuffed with TV and movie pastiches as well as actual clips, endless billboards and movie theater marquees, and sustained bursts of Los Angeles station KHJ, blasting pop tunes and commercials over car radios throughout.


Running parallel to Rick and Cliff's story are glimpses into the more glamorous lives of Rick's Cielo Drive neighbors, Sharon Tate (Margot Robbie) and Roman Polanski (Rafal Zawierucha), whose proximity only makes Rick's exclusion from the New Hollywood club sting more. At a Playboy Mansion party, while Sharon dances with Michelle Phillips and Mama Cass, Damian Lewis drops by as Steve McQueen to explain that Sharon's ex-fiance, hairdresser Jay Sebring (Emile Hirsch), remains in the picture waiting for Polanski to screw up the marriage.


Then there are the clusters of female Manson family acolytes, either dumpster-diving for food or hanging out on street corners to give tourists a thrill. Rick dismisses them as hippie trash, while Cliff is more intrigued, particularly by a flirty nymph in a crochet halter top and denim cutoffs named Pussycat, played by Margaret Qualley in a performance of insouciant sexual authority.


One of the movie's best scenes comes when Cliff drives Pussycat home to the disused Spahn Movie Ranch and has an uneasy meeting with her adoptive family members, including wary earth mother Gypsy (Lena Dunham) and an openly hostile Squeaky Fromme (Dakota Fanning). Cliff knows the place well from the days of Rick's TV show Bounty Law, and his insistence on seeing the owner, George Spahn (Bruce Dern), leaves him with more questions than answers. The classic Western element of a cocksure stranger moseying into a town where he's met by suspicious gazes fits neatly with Tarantino's thematic interest in the outsize influence of Hollywood on American life.


Audiences in Cannes have been urged in a personal note from the director and producers to refrain from plot spoilers, so while it's well known that the movie deals with the period immediately surrounding the Manson murders, let's just say Tarantino puts his own playful spin on that horrific chapter of Hollywood history, which won't be entirely surprising to anyone who's been paying attention to his recent work.


The folks who found the violence against the one significant female character in The Hateful Eight especially noxious will have more to complain about here, while others who respond to the mellow groove of the Rick-Cliff dynamic will possibly find the swerve into gnarly Grand Guignol a little jarring.


Polanski remains a background figure, away on a shoot in England on the fateful night, but Tate floats through the movie like a golden-haired dream goddess in mini-skirts and go-go boots. Robbie is given disappointingly little to do aside from look gorgeous, but she has one captivating scene in which she wanders into a movie theater to watch the Dean Martin spy caper The Wrecking Crew, in which she co-starred, her face lighting up with every audience reaction to her screen character's klutzy comedy.


Tarantino has frequently been more a maestro of the linked vignette than a disciplined narrative storyteller, and that's very much the case here as the bulk of the movie zigs and zags through the experiences of Rick and Cliff, touching on Hollywood lore both based in fact and purely fictional.


A mention that Cliff got away with killing his wife segues to a brief scene snippet with implied echoes of Natalie Wood's death. And there's an amusing faceoff with Bruce Lee (Mike Moh) on the shoot of The Green Hornet, which gets Cliff kicked off the set by the stunt coordinator, played by Kurt Russell in one of many star cameos. But the main fact we learn about Cliff is his loyalty to Rick and his indulgent love for Brandy, the red Rottweiler that shares his trailer out by the Van Nuys drive-in. Still, Pitt's self-satisfied swagger and easygoing warmth haven't been put to such winning use in years.


What Tarantino really gets off on here is playfully recreating the magic of Hollywood 50 years ago. The backlot scenes of Cliff at work are terrific, notably one extended interlude where he's shooting a guest villain spot on a new series called Lancer, appearing with Timothy Olyphant, Scoot McNairy and Luke Perry, in his final screen role, which adds a touching note. The precocious intelligence and seriousness about her craft of an 8-year-old Method actress adds to Rick's self-disgust after too many whiskey sours the night before cause him to keep flubbing lines. And when he returns after a furious pep talk with himself in his trailer and aces a dialogue-heavy scene, the evidence that Rick is indeed a real actor is as much for his benefit as ours. The tears welling in DiCaprio's eyes pack unexpected poignancy.


A rushed account of Rick's six months in Italy shooting spaghetti Westerns (Kill Me Quick, Ringo, Said the Gringo) and Bond knockoffs (Operazione Dyn-o-mite) — a career move orchestrated by Al Pacino as a smarmy agent — feels like a perfunctory genuflection to Tarantino idols like Sergio Corbucci. (The title itself is a Sergio Leone homage.) And the return to the sporadic narration heard briefly earlier and then abandoned for most of the movie is clumsy. But there's as much soulfulness as actorly vanity in DiCaprio's characterization, which makes the struggle of this functioning alcoholic to maintain some career momentum quite touching.


Once Upon a Time in Hollywood is uneven, unwieldy in its structure and not without its flat patches. But it's also a disarming and characteristically subversive love letter to its inspiration, in which Tarantino rebuilds the Dream Factory as it existed during the time of his childhood, while rewriting the traumatic episode often identified as the end of that era.


Production companies: Heyday Films, Columbia Pictures, Bona Film Group Co.
Distributor: Sony/Columbia
Cast: Leonardo DiCaprio, Brad Pitt, Margot Robbie, Emile Hirsch, Margaret Qualley, Timothy Olyphant, Julia Butters, Austin Butler, Dakota Fanning, Bruce Dern, Mike Moh, Luke Perry, Damian Lewis, Al Pacino, Nicholas Hammond, Samantha Robinson, Lorenza Izzo, Costa Ronin, Perla Haney-Jardine, Damon Herriman, Lena Dunham, Kurt Russell, Scoot McNairy, Michael Madsen, Rumer Willis, Rafal Zawierucha
Director-screenwriter: Quentin Tarantino
Producers: David Heyman, Shannon McIntosh, Quentin Tarantino
Executive producers: Georgia Kacandes, Yu Dong, Jeffrey Chan
Director of photography: Robert Richardson
Production designer: Barbara Ling
Costume designer: Arianne Phillips
Editor: Fred Raskin
Visual effects designer: John Dykstra
Casting: Victoria Thomas
Venue: Cannes Film Festival (Competition)

Rated R, 159 minutes