Jake Gyllenhaal may be the Hollywood star of the Encores! staged concert reading of “Little Shop of Horrors,” but he’s not taking the last bow. He’s giving that to Ellen Greene, the stage favorite reprising the role that made her famous in the 1982 Howard Ashman-Alan Menken musical. At the July 2 matinee, as the standing-ovation audience cheered her, she looked genuinely overcome with emotion.

That afternoon performance was one of just three shows the production is squeezing in prior to the July Fourth holiday, a catch-it-if-you-can proposition that has helped make “Little Shop” the hottest ticket in town. And the day after it opened July 1, the quickie run landed the kind of swoony New York Times review that gets the hearts of Broadway producers fluttering.

At very least, Broadway will be scrambling to find a musical for Gyllenhaal to star in. The actor, who’s playing a nebbishy plant-shop employee in “Little Shop,” has already proven himself as a Broadway draw, helping to turn the play “Constellations” into a hit last season. With “Little Shop” he’s shown he can carry a musical, too.

Whether some version of this “Little Shop,” presented as part of the New York City Center Encores! Off-Center program — an offshoot of the series that spawned the long-running revival of “Chicago” — is another question. The event, rehearsed and performed in a very short window of time, had an agreeably loose, informal vibe, with scripts in hand and little in the way of sets or choreography.

That was part of the fun for audiences and, it seemed, for the actors. “Damn scripts,” Gyllenhaal muttered in an ad-lib when his character pricked his finger and drew blood. “Staged readings!”

In this concert version of the doo-wop B-movie sendup (directed by Dick Scanlan), the show’s carnivorous alien plant wasn’t represented by an elaborate puppet, but instead by an actor — at first a young boy (Anwar Kareem), before the plant grew into Eddie Cooper, who donned the bling of a green fake-fur coat and Kanye sunglasses when the plant starts to thrive.

The show’s finale brought down a projection screen on which factoids about the musical and its late co-creator Ashman were shown, underscoring the impression that this particular production was conceived more as a fan-pleasing celebration rather than as a project with commercial legs.

And please the fans it did. Greene, returning to the New York stage for the first time in years, was the audience favorite, killing it on “Somewhere That’s Green” — the I-want number for her battered, good-hearted Audrey — and on “Suddenly, Seymour,” her duet with Gyllenhaal. Cooper had a chance to bring down the house, too, with “Feed Me (Git It),” while Taran Killam yukked it up as the sadistic D.D.S. in “Dentist!”

With the ultra-limited Encores! engagement closing the day after it opened, “Little Shop” will at least give Broadway types something to talk about over the holiday weekend. Now who’s got a musical for Gyllenhaal to star in?