In 2003, a mysterious billboard popped up in Los Angeles, with a sinister headshot and a phone number, advertising a movie called “The Room.” Playing in one theater, the romantic melodrama written, directed, produced by and starring the inimitable Tommy Wiseau was a flop, until cult movie fans discovered possibly the best worst movie ever and made it a hit. Now the story of the making of that movie is itself a movie, “The Disaster Artist,” directed by and starring James Franco as Wiseau. And it’s entirely appropriate that this movie about a very bad movie is, in fact, very good.

“The Disaster Artist” is also very, very funny, intentionally so, about someone who never intended to be funny, who ended up embracing the sometimes loving, sometimes derisive laughter directed toward him and his film. Wiseau is just so unabashedly himself, completely without shame. In a kooky yet vulnerable and heartfelt performance, Franco gets right at the heart of what makes Wiseau a true hero — his sheer willingness to try — and that is what makes “The Disaster Artist” work so well.

Scott Neustadter and Michael H. Weber adapted the script from a memoir about the making of “The Room” written by Wiseau’s unlikely collaborator, Greg Sestero, played by Dave Franco. Their script emphasizes the friendship between Greg and Tommy, a duo of dreamers who are more alike than they might seem.

They meet in a San Francisco acting class, where the self-effacing and naive Greg is drawn to Tommy’s strange charisma and unfiltered fearlessness.

The pair make a pact to make it in Hollywood, and soon they’re crashing in Tommy’s L.A. pied-a-terre, getting agents and going on auditions. While Greg gains some traction, everyone in L.A. wants to pigeonhole Tommy, with his long hair and his accent, as a villain, despite his protestations that he’s the All-American hero. Downtrodden after being rejected again and again, Tommy is inspired to make his own movie, and thus, “The Room” is born.

As Tommy frets over the premiere night reception of his finished film, which has devolved into raucous laughter and chanting at how awesomely bad it is, Greg comforts him in the lobby. “How many people do you think have done this?” he asks Tommy. “I dunno, a thousand?” he responds. It’s a joke, but that interaction is also the core of what this movie is about. Tommy did what so many haven’t — he said he was going to make a movie and he did.

“The Disaster Artist” is a celebration of sheer effort and follow-through, a willingness to put oneself out there, facing judgment and scorn, hoping always for acceptance. That Tommy was embraced, despite the unexpected form it took, is the happiest ending of all, with “The Disaster Artist” the bow on this crazy, real-life Hollywood story.

MOVIE REVIEW

“The Disaster Artist”

Grade: B+

Starring James Franco, Dave Franco and Seth Rogen. Directed by James Franco.

Rated R for language throughout and some sexuality/nudity. Check listings for theaters. 1 hour, 43 minutes.

Bottom line: A look at a real-life story of effort and follow-through