Like such kindred spirits in quantity over quality as Tyler Perry and Joe Swanberg, James Franco has made a crapload of movies. Sooner or later, he was bound to deliver a good one. But who would have thought his adaptation of Greg Sestero’s “The Disaster Artist,” an outrageous blow-by-blow account of the actor-turned-author’s friendship with the aggressively untalented and infinitely enigmatic creator of one of the worst movies of this century — “The Room” writer-director-star Tommy Wiseau — would turn out to be the best and most professional entry on his own résumé?

That’s a claim not without caveats, mind you. The version that world premiered at the South by Southwest film festival was presented as a “work in progress” — where it killed to a room full of “The Room” obsessives, many of whom stuck around for a midnight screening of Wiseau’s disasterpiece. And even though IMDb lists no fewer than 37 directing credits for Franco (which doesn’t include practically any of his multimedia art projects, from the Sundance-launched live reading of a classic “Three’s Company” episode, to the Berlin gallery-screened short he made wearing a dildo on his nose), the bar had been set pretty low. Franco is a filmmaker whose ideas are nearly always more interesting than their execution, so fans of “The Room” had reason to be concerned when he announced his intention to do “The Disaster Artist.” Would this be just another patience-trying goof from the prolific prankster — a half-baked, fun-to-make movie that audiences would find insufferable to watch?

Fortunately, the answer is: No, “The Disaster Artist” is a real movie, backed by a legitimate studio (Warner Bros. and its newly relaunched New Line division), featuring a handful of bona fide Oscar nominees, boasting a genuine capacity to delight, whether or not the audiences in question have seen “The Room.” And as a bonus, it makes a fascinating addition to his growing oeuvre of self-immolating performance art. Just as Johnny Depp gave his career-best performance as Z-movie auteur Ed Wood, Franco achieves what could become his most iconic role — surpassing even “Spring Breakers” rapper Alien — as Tommy Wiseau, international man of mystery.

Just who was Wiseau, you ask? When “The Room” opened in June 2003, audiences had no idea what to make of its star, a narcissistic homunculus whose hulking physique and long black hair suggest a Harlequin Romance cover gone horribly wrong, and who sounds like he might have been raised in Transylvania. Though Wiseau had four-walled two Los Angeles screens to give “The Room” an Oscar-qualifying run, fewer than 200 people paid to see the movie on opening weekend. A withering Variety review blasted “the overall ludicrousness of a film whose primary goal, apparently, is to convince us that the freakish Wiseau is actually a normal, everyday sort of guy.”

But then a funny thing happened: Ever so gradually, word got out about just how awful the movie was — how this near-tragic waste of an estimated $6 million budget might be appreciated as an accidental comedy — and audiences started coming to see for themselves. In time, attendees (many of them regulars) got bolder and more cruel, shouting back at the screen and devising routines that transformed Wiseau’s ineptly miscalibrated melodrama into a “Rocky Horror Picture Show”-esque audience-participation phenom.

But as “The Room’s” popularity grew, so too did the questions that surrounded it: Who was its perplexing outsider auteur? Why did every creative decision he’d made on the film seem to contradict how any semi-competent filmmaker might have handled it? And how did he feel about being laughed at for a movie that seemed to take itself so seriously? Granted, Wiseau has unusually thick skin — that much is clear just looking at the leathery actor, whose shield-your-eyes love scenes are the apotheosis of “gratuitous sex and nudity” — but there’s a vulnerability to the man that makes him fascinating. What must it be like to get inside Wiseau’s head?

That is both the genius and central failing of Franco’s “The Disaster Artist” adaptation, which gave the actor the opportunity to spend several weeks lost in character. Co-star Dave Franco, who plays Sestero, claims that his brother disappeared for the duration of production. Much as he did on his Method-earnest 2001 made-for-TV James Dean biopic, Franco uncannily reinvents himself in the guise of his subject — this time, for comic, rather than tragic effect. But what insights did he learn while deep inside? And how did he miss the dimension that could make the seemingly alien Wiseau a normal, everyday sort of guy?

It’s all there in Sestero’s source material, as the book, however damning, happens to be written by Wiseau’s best friend — arguably the only man on earth who can empathize with and possibly understand the riddle behind “The Room.” Sestero is one of those dime-a-dozen 6’2″ Hollywood hunks with good looks to spare and no acting talent to speak of. Dave Franco, on the other hand, is Tom Cruise-tiny, an adorable, slightly less stoned-looking Mini-Me version of brother James. Watching them appear side by side, it’s hard not to be distracted by their nearly identical smiles, making it nearly impossible for Franco the elder to exploit the obvious: that Wiseau had some sort of asexual man-crush on Sestero, whom he called “Babyface.”

“The Disaster Artist” begins in 1998, when a painfully shy Sestero (butchering a scene from “Waiting for Godot” in a San Francisco acting class taught by Melanie Griffith — the first of many laugh-on-recognition cameos by screen legends) was dazzled by Wiseau’s epically over-the-top interpretation of the “Stella!” scene from “A Streetcar Named Desire,” delivered in an impossible-to-place European accent. No one else in Sestero’s acting class knew what to make of Wiseau, but Sestero made friends, and the subsequent scenes are as hilarious as one could hope — though somehow lacking in the human dimension.

To this day, Wiseau remains a tragically misunderstood character, drawn to a career for which he is uniquely unsuited. It wasn’t just the accent (he claims to be from New Orleans), or his potato-skin looks (he says he’s Sestero’s age: 19), but the fact that Wiseau could barely remember his lines, and when he spoke, the syntax was almost Yoda-like in its peculiar garbling of the English language. The script by “500 Days of Summer” co-writers Scott Neustadter and Michael H. Weber doesn’t shy away from moments of abject humiliation, as when an L.A. acting teacher (Brett Gelman) candidly advises him to abandon his leading-man dreams and instead try to land villain roles: “Have you looked at yourself? You have a malevolent presence,” he tells Wiseau. And then, of course, there’s the film’s eventual premiere, when Wiseau first endures the feeling of having audiences laugh at his work, for which he had bared his soul and burned several million dollars of a fortune whose origins are anybody’s guess (although “such nosy person” Sestero’s best guess in the book, involving a shady business called Street Fashions USA, isn’t even mentioned in the film).

“The Disaster Artist” takes a curiously long time to get to the actual making of “The Room,” and one might expect all that lead-up — during which Sestero and Wiseau move to L.A., where they share the latter’s one-room pied à terre — to serve in establishing the foundation for the dysfunctional buddy movie this really ought to be. But somehow, in accentuating Wiseau’s weirdness, Franco overlooks his soul.

From “Foxcatcher” to “Behind the Candelabra,” recent homoerotic biopics have exploited the way that a wealthy, insecure older man goes to incredible lengths to impress the object of his fixation, and while there are a few such scenes (Wiseau’s jealousy rages anytime Sestero’s attention shifts to flirtatious bartender-turned-girlfriend Amber, played by Alison Brie), the movie seems undecided on what makes Wiseau tick: Is it a craving for fame? A desire to impress Sestero? Theirs was a textbook Svengali-Trilby relationship, and yet, the dynamic is oddly distorted by Dave Franco’s involvement.

Among the many ways in which “The Disaster Artist” serves as a wink-wink meta-commentary on itself, on Hollywood (as seen and understood by a filmmaker who clearly doesn’t take it seriously, as evidenced by his 2011 phone-it-in Oscar co-hosting gig), and on the persona that is James Franco, there’s an undeniable spark of inspiration in his decision to reenact the making of an impossibly bad movie with his brother Dave, since the duo had done a series of “Acting With James Franco” shorts for Funny or Die that began his descent into the elaborate and ongoing deconstruction of his own celebrity.

In a sense, “The Disaster Artist” could be the master class on how not to make a movie. But that’s a pretty elaborate in-joke on which to squander the casting of the film’s lead role, especially when any number of genuinely great actors would have leapt at the opportunity to mock their profession. That much is clear from the caliber of performer drawn to participate in the movie’s tiniest roles: Sharon Stone shows up as Sestero’s agent. Bryan Cranston plays himself. Judd Apatow (who effectively discovered Franco on “Freaks and Geeks”) appears as an easily peeved Hollywood producer. Seth Rogen depicts exasperated script supervisor Sandy Schklair. The great Jacki Weaver wrestles with an impossible line (“I got the results of the test back, I definitely have breast cancer”). An unrecognizable Zac Efron plays the over-actor responsible for playing menacing gangster Chris-R in “The Room.” And Josh Hutcherson hilariously embodies the 27-year-old whom Wiseau cast as a mentally disabled teen. (And that doesn’t even include those like Zach Braff and J.J. Abrams who endorse Wiseau’s magnum faux-pus in the film’s prologue.)

Whether or not audiences have previously seen “The Room,” there’s satisfaction simply in witnessing such actors parody the process that went into making it. And for those who do know the movie, there are no shortage of before-the-fact nods to ingredients that would later filter into the project: as when Wiseau and Sestero play an awkward game of football (as they later would in “The Room”), or a couple of melodramatic moments staged on the roof of Wiseau’s apartment building (a venue he would inexplicably approximate via lousy greenscreen on a soundstage for the film).

Although Franco evidently wasn’t interested nearly enough in Wiseau’s motivations, “The Disaster Artist” does succeed in capturing the sheer ineptitude of his endeavor, including details that many don’t know — and might never guess — such as Wiseau’s decision to shoot “The Room” in both digital and 35mm formats, or his insistence on having his own personal bathroom on set. It also provides a revisionist take on “The Room’s” own transformation from failed Tennessee Williams knockoff to inadvertent comedy, recasting the film’s long-delayed premiere as the moment the switch happened. (For the true story of how two discriminating bad-movie connoisseurs, Michael Rousselet and Scott Gairdner, were its first and only champions, hunt down Sestero’s book — or better yet, the audiobook, in which he does an impersonation of Wiseau even better than Franco’s.)

The film ends with a series of uncanny side-by-side recreations that reveal Franco’s deep love and respect for “The Room.” Nothing like his slapdash “Idaho” (a freeform 2011 experiment in which Franco remade Gus Van Sant’s “My Own Private Idaho” from an alternate script), these bonus scenes were shot by “This Is the End” DP Brandon Trost and prove that Franco is capable of making a professional-grade movie when he applies himself.

Clearly, despite the undeniable comedic potential of playing Wiseau in all of his tyrannical capriciousness, Franco feels a deep empathy for the man, evident even when depicting Wiseau’s frequent tardiness, his virtual inability to deliver his lines, and his angry tirades against a justifiably skeptical cast and crew (all of them grateful for the gig, and some of whom saw “The Room” as their big break). And yet, missing from his otherwise outstanding performance is some sense of the wounded little kid locked deep within, trapped in a room of Wiseau’s own making, who merely wants to be loved.

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