Joss Whedon has created so much cult entertainment that he has become a cult figure himself. He’s that rare writer/producer/director with movie-star status to the legion of fans of “Buffy the Vampire Slayer,” “Angel” and “Firefly,” to name a few of his creations. And, oh, yes, to the zillion fans of last year’s biggest box-office success, “The Avengers.” There’s even a Joss Whedon action figure.

So it’s a little surprising to find him sitting alone in the crowded Trio restaurant of the Four Seasons Hotel, looking out a picture window onto Lady Bird Lake during the movie madness of South by Southwest. No one at the other tables seems to recognize him; must be the bad likeness of the action figure.

That’s fine with Whedon, who spends huge hunks of time as the center of attention on crowded sets. “Being alone is not a problem for me,” he says. “I’m not a real people person. If we are not creating something, eventually, I don’t know what to do with all my friends. I get antsy. I’m a writer; I like to be alone a lot of the time.”

This is back in March, and Whedon is here to promote his post-“Avengers,” save-his-sanity movie, the screwball romantic comedy “Much Ado About Nothing,” a faithful, if much abridged, modern-dress version of a pretty terrific play by another cult writer, William Shakespeare. Whedon is a lifelong Shakespeare fan and has long wanted to do a film. Ironically, the gargantuan success of “The Avengers” helped it happen.

“I am the most privileged person I know,” Whedon says. “I work on comic-book movies, which I’ve wanted to do my whole life, and I can film Shakespeare, which I’ve wanted to do almost as long. The first time I saw “Much Ado,” in London when I was in high school, I was blown away.”

Whedon shot the low-budget movie in 12 days, in his own home, with a cast of his action- and fantasy-film pals. Quite a switch from the many months he spent on giant sets for “The Avengers.” The movie, opening Friday in Houston, is getting prime reviews and drawing record art-house box office. No, not quite like the $1.5 billion “The Avengers” did worldwide, but then “Much Ado” doesn’t have guys in butch leather and steel costumes wielding magic hammers and such.

“It was an incredibly selfish act” to make “Much Ado About Nothing,” Whedon says, not sounding at all sorry. “My wife, Kai (Cole), suggested it. ‘You need to film this, and you’re going to do it instead of taking me on a vacation for our 20th anniversary.’ So when I say selfish, I mean very specifically. I spent the first two days apologizing to everybody (on set), until I realized, ‘Oh, they’re having as much fun as I am, that’s why they’re here.’ ”

Almost everyone on set was in the unofficial Joss Whedon stock company – people who have been in other Whedon works: Amy Acker (“Angel,” “Dollhouse,” “The Cabin in the Woods”), Alexis Denisof (“Angel,” “Dollhouse,” “The Avengers”), Nathan Fillion (“Firefly,” “Serenity,” “Dr. Horrible’s Sing-Along Blog”), Clark Gregg (“The Avengers”) and so on. Most of them had already been coming to Whedon’s house to do play readings.

“Joss would have little Shakespeare brunches at his house over the years,” says Fillion, who also is around at SXSW. “He would say ‘OK, who’s available? OK, you’re playing so and so.’ ” Whedon would write edited versions and give out scripts for the reading. “Then we’d have a wonderful brunch,” Fillion says.

Part of the fun of watching this “Much Ado About Nothing” is sensing that all the players are having a kick. “I can pretend I’m having fun,” says Fillion. “I really had fun on this.”

“It’s part of the Whedon genius,” says Gregg. “This is just going to be some fun. He creates this environment where you feel, I’m OK. I’m scared but let’s try this. That’s not a small thing.”

Whedon already is back to work on “The Avengers 2”; the demanding power of another potential $1.5 billion cannot be denied for long and takes a long time to create. He says “Avengers 2” will be out in 2015. “And I’m already behind on the script.”

But he is not complaining.

“This is the life I dreamed of living. I’m making a great big movie that I’m incredibly passionate about (“Avengers 2”). I feel like I’m going to be able to do things I’ve never done, and grow as an artist.

“At the same time, doing a smaller project (“Much Ado”), reconnecting with a different audience and the actors that I’ve grown to love. It’s life restoring.”

Whatever he does, he plans to keep doing it with friends as much as possible.

“It’s called show business,” Whedon says. “But for me, from now on it is show friends. Deal with it. For me, there are two things in this life, the work we make and the time we spend making it. If that time is arduous, then half your life sucks. And that’s not OK with me.”