In 1978, as the world mourned the loss of Elvis Aaron Presley, a velvet-voiced doppelganger arrived on the scene to claim his place in the hearts and minds of America. Shortly after charting a meteoric rise to fame in the ghostly shadows of Elvis’s legacy, however, one of rock history’s most curious oddities disappeared into obscurity—the victim of a ruthless recording industry, his own ambitions, and the very voice that briefly brought his life uncannily close to the King of Rock and Roll.

Orion Eckley Darnell was a tall drink of water who hailed from Ribbonsville, Tennessee, and sounded, eerily, exactly like the recently departed Presley. He burst out of nowhere into the music world the year after the icon’s death first by lending his gentle Southern drawl to a Jerry Lee Lewis album of duets, crooning “Save The Last Dance For Me” with an unmistakably Elvis-like timbre.

To Elvis fans the music had an ethereal quality, as if they were hearing an Elvis song they never knew existed. So soon after losing Presley to a drug-fueled heart attack at the age of 42, it seemed the impossible had happened: Elvis was alive and well, singing to his adoring public from beyond the grave.

The record was a smash and Elvis’s own label saw the potential. Borrowing unabashedly from a fantasy novel about a rock ’n’ roller who fakes his own death to escape the pitfalls of fame, Sun Records soon introduced the man behind the voice in Reborn, an album whose cover shamelessly depicted an Elvis-like figure crawling out of a coffin back onto the stage.

Orion started making public appearances, always wearing bejeweled masks that obscured his face—Elvis meets Zorro, with a dash of Liberace sparkle. Hot-blooded masculinity coursed through his limber frame, clad in the silk shirts and polyester wing suits of Elvis in his prime. Fame, record sales, and an endless string of groupies soon followed. Orion was on his way to stardom.

There was just one problem: There was no Orion. There never had been. Orion’s hometown of Ribbonsville, Tennessee, was as made-up as his fictional biography and as nonexistent as Dixieland, the Graceland-esque mansion he supposedly lived in, and where fans could send him mail.

The man behind the mask was really a Southern hopeful named Jimmy Ellis, the adopted son of a horse farmer from Orrville, Alabama. He’d grown up dreaming of a career in music but didn’t get a real shot until late in life, when Sun Records owner Shelby Singleton conspired to capitalize on posthumous Elvis mania by launching an elaborate pop fantasy around the character of Orion—a gimmick that worked all too well, as a frustrated Ellis eventually realized.

His bizarre and colorful saga is chronicled in Orion: The Man Who Would Be King, a documentary hitting theaters Dec. 4 that finally gives the spotlight to Ellis, not Elvis, and examines how he became trapped by his own talent and ambition.

The film recounts Ellis’s early life in Alabama, interviewing old friends who recall a gifted young man who surprised everyone when he opened his mouth to sing. Presley’s voice poured right out of Ellis, whose natural born talents led him to pursue a recording career under his own name in 1964. But early brushes with opportunity escaped him. After going to college, he returned home to learn the family business.

Ellis married, divorced, remarried, and re-divorced—a precursor to his famously tumultuous relationships with women, the film hints—but his restless soul never lost sight of his real dream. He moved to Los Angeles, only to reluctantly return home again after spending all of his money on groomers, choreographers, and training he’d hoped would help turn him into a star.

It was a once-in-a-lifetime confluence of events that led to the birth of Orion.

The real Elvis died on Aug. 16, 1977, leaving a void in the pop music landscape. Novelist Gail Brewer-Giorgio published her novel Orion, offering the built-in backstory of an Elvis figure who lived on even when the world thought he’d perished forever. Meanwhile, Presley sound-alike Ellis finally got Singleton’s attention by sending the exec a recording of two Elvis covers, “That’s Alright, Mama” and “Blue Moon of Kentucky.”

Smelling opportunity, Singleton shrewdly pieced together a viral stunt by lifting the myth straight from Giorgio’s book and contracting Ellis to a deal singing tunes in the style of Presley under the condition that he wear a mask and that he could never, ever take it off. Even Giorgio, who never got a dime from the unlicensed theft of her Orion property, seems impressed by the sheer ballsiness of the men who screwed her over as she recalls that period for the camera: “I got nothing. Zero, zilch, nothing.”

The Man Who Would Be King recounts how the charade only piqued the curiosity of Orion’s adoring public, a fandom in need who was just as complicit in the shared fantasy. He sounded just like Elvis, swiveled his hips like Elvis, and played to the crowd like the King himself. Fans distraught over the real Presley’s death found a living, breathing cipher to transfer their adoration onto. He recorded nine studio albums in the span of a few years, toured the globe, and even headlined with KISS, leaving a swooning trail of groupies in his wake.

In interviews with the now-grown son, the old pals, and the girlfriends who knew him best, director Jeanie Finlay sees Ellis through the gaze of those around him: A charismatic performer in his own right who belonged on the stage, but became increasingly exasperated by the persona he was forced to wear even as it made him more and more famous. Ellis bristled at the suggestion that he was a mere Elvis impersonator. He made national media appearances, but wasn’t allowed to reveal his true identity. His true self was inextricably buried within the Orion mystery, which was itself inseparable from the specter of Elvis Presley.

The mask became a burden that stifled Ellis, who desperately wanted to be recognized as an artist in his own right—known by his own name, for his own voice. “He hated the mask the entire time he wore it,” remembers a bandmate. Even he knew he was being exploited by a bad contract that left all the riches in the Sun Records ledgers. Ellis’s discontent came to a head on New Year’s Eve 1983, when he unmasked himself in a dramatic onstage reveal in front of thousands of fans. “He had to be known,” offers songwriter Carol Halupke. Singleton ripped up his contract shortly thereafter, and the Orion fantasy burst.

The Man Who Would Be King assembles an intriguing account of the origin and fate of Orion the rock and roll star who never fully existed, including a cringe-worthy postscript detailing Ellis’s post-prime stabs at a Rick Springfield-styled comeback. But Finlay’s real accomplishment is her exploration of what drove Ellis to live in the myth as long as he did. She pieces together a portrait of a talent searching for his own identity and validation, revealing that Ellis had been the product of wedlock whose mother had given him up at the age of 2 and that his father, identified only as “Vernon” on his birth certificate, might have been Vernon Presley. It’s tempting to buy into Finlay’s evidence that Ellis was the lost half-brother of the real Elvis, a long-held theory among Orion fans. The shadow of Elvis was one Ellis had been living in and hyperaware of his whole life; he’d even recorded a song about it, titled “I’m Not Trying To Be Like Elvis.”

Ellis’s own eerily disembodied voice testifies via archival audio, wistfully recalling the part he played in the ruse. “We preyed not only on the fans but the press,” he says, revealing that he’d always hoped the truth would go public and free him to have a recording career as himself. “I’m happy,” he declares unconvincingly, adding, “I think happiness is a temporary state of mind.” Unfortunately, Finlay does not explain the source of these interviews, a minor frustration that’s amplified once the conclusion of his wonderfully strange American dream is revealed.

The tale of Jimmy Ellis was already bittersweet before it came to a tragic end in 1998, a footnote in the annals of pop culture lore to most of America that nevertheless gives The Man Who Would Be King its surprisingly emotional wallop. It’s easy to see why another Jimmy—Jimmy Fallon—once mocked Orion on late-night television decades after his ephemeral rise and fall, donning a blue mask to warn a snarky new generation of pop consumers away from Ellis’s Elvis-lite output. Through Finlay’s lens we get a more intimate chance to empathize with the man who once was Orion when a much older Ellis appears via home video, warbling alone in his car as he drives through the countryside—no longer in demand from an adoring public and long forgotten by the world, but still singing his heart out.