It happens all the time in Hollywood: A friend has a dream of making a movie and wants to hire his friends as cast and crew. But most of the time, those dreams remain just that when the funding for those projects doesn’t materialize.

For South Pasadena-based actor Greg Sestero, however, the dream became reality when his friend Tommy Wiseau managed to raise $6 million to write, direct and star in a movie called “The Room.” Keeping a promise he made years before when the two thespians met in a San Francisco acting class, Wiseau hired Sestero to be his co-star.

That should have been a happy ending, with the film rising out of Sundance-style festivals to become an indie sensation. Instead, “The Room” became wildly popular for an entirely different reason: it’s regarded as one of the great camp classics of all time, a movie considered so bad it’s brilliant.

Its monthly midnight showings at the Laemmle Sunset 5 theater in West Hollywood routinely sell out all five of the theater’s screens simultaneously, with crowds that have turned the viewing experience into the craziest interactive movie party since “The Rocky Horror Picture Show.”

The entire crowd will walk out for five minutes during an especially long and graphic sex scene before reclaiming their seats, or members will throw spoons at the screen whenever a framed picture of a spoon appears onscreen (that happens a lot). But, on its own bizarre terms, the film is a hit, and Sestero is proud to note that Saturday’s screening should be the biggest yet; both BBC and a Canadian news team are sending cameras to record the madness.

“I didn’t think this was drama or comedy,” explains Sestero. “I just thought this thing is going to be wildly entertaining. I think with Tommy, that’s one way to describe him — whether it’s an acting class or hanging out.”

Sestero first showed interest in show business by writing an unproduced sequel to “Home Alone” that the original film’s writer, John Hughes, acknowledged warmly. He notes that “The Room,” amazingly, has opened new doors for him, including upcoming roles in two films by Regent Entertainment, producers of the Oscar-nominated “Gods and Monsters.”

Between roles, he and Wiseau hopscotch the planet hosting screenings in cities from London to Sydney. While he’ll be in New York during the Aug. 29 LA screening, Sestero sounds like he’s ready to defend the film for a long time to come.

“It was one of the three top-selling DVDs on Amazon a few weeks ago,” says Sestero. “We were at Comic-Con [comic book convention in San Diego] last month and it’s insane how many people know about it. All I can say is people are riveted. Except for the sex scene … not one person leaves their seats in the entire movie. How often do you notice that?”