When Robbie Williams told an interviewer that he felt like a performing monkey, he didn’t mean it literally. But that’s exactly how “The Greatest Showman” director Michael Gracey interprets the remark in “Better Man,” an off-the-wall musical biopic that surely would have seemed banal — as opposed to downright bananas — had it featured a flesh-and-blood actor in the Robbie Williams role.

Gracey takes audiences through all the expected beats of Williams’ career, from his breakthrough as a member of Take That to his record-breaking solo concert at Knebworth, but does so with a CG chimpanzee standing in for the Britpop bad boy. Against all odds, that gimmick works, distinguishing the project from so many other cookie-cutter pop-star hagiographies. If you want to fawn over this boy-band backup singer-turned-solo superstar for four hours, check out the “Robbie Williams” doc series on Netflix. But if you want to see a chimp doing coke with Oasis, or getting a fateful hand job in front of manager Nigel Martin Smith (Damon Herriman), this is your movie.

By inserting what looks an awful lot like Caesar from the new-and-improved “Planet of the Apes” franchise in Williams’ place, Gracey dodges the main question folks have about musical biopics — namely, “Who’s gonna play him?” So if you worry whether the whole chimp thing could be distracting, don’t forget how barmy it felt pretending that Elton John’s life would have turned out the same if he’d looked anything like Taron Egerton, or that a pair of false teeth could transform Rami Malek into the strutting sex symbol that was Freddie Mercury.

Recently, “Stardust,” “Back to Black” and even “Elvis” were undermined by the chasm we felt between those films’ lead actors and the pop icons they were portraying. By contrast, “Better Man” falls squarely in that uncanny valley, and for once, that’s a good thing. First off, Americans don’t really know who Williams is, making it easy to accept whatever Gracey puts in his place. Better still, his simian CG counterpart proves far more expressive than most human actors, meaning the movie is built around an animated performance powerful enough to wring tears.

With “Better Man,” the musical maestro adds ridiculously complicated technical challenges to his résumé — like the jaw-dropping “Rock DJ” number staged in London’s busy Regent Street, shot over four days and stitched together to look like a single unbroken take, or the “Come Undone” sequence where he speeds away from the boy-band breakup, nearly smashes his car into an oncoming bus and plunges into a sea of paparazzi. These numbers deliver essential emotional information in unimaginably dynamic ways, leaving traditional tuners in the dust.

And yet, “Better Man” suffers from the same issue that afflicts nearly all pop-star portraits: Instead of picking a significant chapter from their subjects’ lives, these biopics typically take the cradle-to-the-grave approach (or cradle-to-rehab, as the case may be). That works for docs, but when it comes to dramatic retellings, the strategy forces the world’s most fascinating characters into familiar arcs: First they demonstrate natural talent, then they’re discovered, then they become insanely rich and famous, only to sabotage it all with addiction, infidelity and ego. If they’re lucky, they don’t OD, assuring normies everywhere they’re better off not being famous.

“Better Man” wants to be “All That Jazz,” but it falls back on the redemptive life-story formula, introducing Robbie as a boy — or in this case, an adolescent chimp, looking scrawnier (and a great deal hairier) than his peers. Little Robbie’s bad at sports, worse at school, but a natural clown, as he learns during a school play. Robbie gets that cheeky streak from his father, a cabaret comedian (stage name Peter Conway, played here by Steve Pemberton) who leaves home to pursue his own showbiz dreams when Robbie is just a lad.

The truth is more complicated, but a stunted man-child searching for Dad’s approval makes Williams relatable. Gracey extensively interviewed the superstar about his life, then constructed the narrative he wanted to tell with co-writers Simon Gleeson and Oliver Cole. His angle is frustratingly familiar, though the execution is downright astonishing — we’re talking Wachowski-level ingenuity as Gracey fashions sophisticated montages where you can’t even spot the cuts.

Consider the scene where Williams learns his most unconditinoal supporter has died, just before playing his biggest show. The camera starts with a tight close-up on Robbie’s eyes, then pulls out to reveal him suspended upside down above the stage, rotating 180 degrees as it flies over the heads of several thousand fans. His eyes are the best thing about that scene — and every scene. They make all the difference: dazzling green and stylized to look more human than chimp-like. Gracey’s visual effects team (led by Wētā whizzes Luke Millar and Andy Taylor) studied hours of archival footage to get the singer’s facial expressions just right, so every squint, wink and scowl corresponds to the real Robbie.

Disarmingly unfiltered at times, Williams swears up a storm, dropping expletives (and trou) without warning — an irreverent trait Gracey slyly re-creates here, placing the chimp in familiar photo shoots. He even offers a version of the “Rock DJ” music video, in which Williams strips down to his insides. The star’s ape avatar goes through a staggering range of emotions over the course of the movie, from being smitten with fellow pop star Nicole Appleton (Raechelle Banno) to feeling devastated by her decision to abort their child for a No. 1 hit. Even his bisexuality is fair game, making “Better Man” a better movie than “Bohemian Rhapsody.” Same goes for his clinical depression — though the death match between all of his different personas (which plays out like “War for the Planet of the Apes”) takes his self-destructive tendencies a step too far.

No matter how dark Williams gets, he remains an undeniably charming character, rendered more so by the monkey thing. Frankly, Gracey’s chimpanzee conceit was always a stretch, since the “performing monkey” put-down really only applies when Williams is doing someone else’s bidding. Behind the CG ape is a real actor, Jonno Davies, who performed his trickiest scenes on set, including much of Ashley Wallen’s inventive choreography. While it’s hard to say how much of Davies’ work survives, the finishing-touch animation is so good, the Academy needs to find the right category in which to acknowledge it.