If it wasn’t for Youtube, you’d have a helluva time convincing anybody under the age of 30 that Tiny Tim existed, or even could have existed.

Androgynous ahead of his time, with a trilling falsetto that could crack glass, style anti-icon, a singular talent with a pop repertoire that covered half a century and certainly the greatest novelty act of the Swinging Sixties, if not all time, he was one of a kind.

Herbert Butros Khaury got his start in a literal “freak show” on Times Square, blew up the pop charts in the Summer of Love and when he got married on TV’s “Tonight Show,” “they had brown-outs,” power outages, as over 50 million people stayed up late to tune in.

Johan Von Sydow’s “Tiny Tim: King for a Day” celebrates the man who made his own myth in a film that ranges from gloriously giddy to Pagliacci sad, capturing his star turns and his very last performance, collapsing on stage one time too many in Minneapolis in late 1996.

Using old TV and film clips, interviews and performances, with his only modern analog, “Weird Al” Yankovic reading entries from his diary, “King for a Day” (which takes its title from one of the ancient pop standards that were a part of his repertoire) paints a portrait of a talented but fragile soul who endured punative parents and audience abuse and pelting in his earliest performances, and some of his last ones as well. But he still carved out his unique place in American pop culture.

He was sought out by Dylan, filmed by Andy Warhol and lionized in New York’s folk music scene of the late ’50s and early ’60s, appreciated for “the unique beauty” of his “singing the sissy way” style.

Peter Yarrow, Tommy James and Wavy Gravy sing his praises, with hippy icon Gravy remembering how hearing Tim “cooked my brain.”

TV producer George Schlatter recalls the meeting he was dragged from to hear this long-haired “weirdo” (his long locks predated The Beatles by years), an audition that would make his series, “Laugh In,” the smash it became. With NBC telling him “You can’t put this on, he’s a freak!” Schlatter threw Tim on stage with unsuspecting co-host Dick Martin, and history was made.

The corny Tin Pan Alley novelty “Tiptoe Through the Tulips” became Tim’s signature, and with Sinatra’s Reprise label (which signed him pre-TV — because like Dylan and Wavy Gravy, they KNEW) behind him, Tiny Tim conquered the pop music world.

If Tiny Tim ever gets a “Bohemian Rhapsody” movie biopic, the peak moment has to be not his many TV appearances on “Ed Sullivan” or his “Tonight Show” wedding to Miss Vicki, but his triumph at the Isle of Wight music festival, serenading 500,000 paying customers with “There’ll Always Be an England” through a megaphone to give it that Rudy Vallee/old time radio sound, to awed and delighted applause.

Von Sydow, who has documentary biographies of opera singer Jussi Bjoerling, writer Marie Kandre and mysterious artist Nils Olof Bonnier to his credit, takes Tim’s artistry seriously, first scene to last.

As hilarious as it is hearing Tiny Tim, playing the ukulele and covering “People are Strange” by The Doors, as amusing as his other covers — from Jeanette MacDonald Great Depression ditties to Bill Haley and the Comets and disco standards — can be, the guy was a walking, high-notes-hitting encyclopedia of 20th century pop.

The “Greatest Generation” types who interviewed him back then recognized his homages to Russ Colombo and Bing Crosby, Rudy Vallee and even Jeanette MacDonald as daft and yet adoring.

The long slide toward the end seems particularly poignant here, reduced to touring with circuses and playing fairs and school gyms, married three times, hints of being too open to the attentions of underage groupies (not THAT open).

His diary entries, where he frets over “sin” real and perhaps exaggerated, chart a “never-fits-in” outsider from rejection to “biggest star in the world” glory with a pathos you don’t expect, just as his TV interviews often saw him soberly drop “the act” to reveal he was pretty much exactly as he came off — nostalgic, courtly and not at home in this world.

But Von Sydow paints a compelling and very entertaining portrait of a showbiz original who found a niche, made his mark with an act famed for its shock value, and yet dabbled in most every musical style to come along after he broke big because he could and would try anything, and do it justice, no matter how high his voice got or how much he rolled his eyes.

MPA Rating: unrated

Cast: Tiny Tim, Susan Khaury Wellman, Peter Yarrow, Wavy Gravy, Tommy James, George Schlatter and Miss Vicki.

Credits: Directed by Johan Von Sydow, script by Martin Daniel. A Juno release.

Running time: 1:15