Michael Bennett, center, and members of the cast of the documentary film Every Little Step get ready for a Chorus Line production number.

Sony Pictures Classics / Martha swope

Watching Every Little Step, a new documentary by James D. Stern and Adam Del Deo, is a bit like walking through a hall of mirrors. Life imitates art, art reflects life, and after a while the distinctions threaten, quite pleasantly, to blur altogether.

The film follows a group of mostly young dancers and singers auditioning for parts in the recent Broadway revival of A Chorus Line, a musical which is itself built around the auditions of 17 mostly young Broadway-besotted dancers and singers.

The premise of Every Little Step is no less inspired for seeming so simple and obvious, and it pays tribute to the durability and continued relevance of A Chorus Line, which first opened in New York in 1975, before many of the performers in the movie were born.

A Chorus Line gives voice to deep, widely shared anxieties and aspirations, but its big themes are grounded in the lives, voices and bodies of individuals. And so the thousands of auditioners who show up, at the start of Every Little Step, for the first casting call — and who over the following months are winnowed down to scores, then dozens and finally a few singular sensations — are hardly faceless or interchangeable.

Still, there is only time to become acquainted with a few of the thousands of auditioners who show up, at the start of Every Little Step, for the first casting call — and who over the following months are winnowed down to scores, then dozens and finally a few singular sensations — of them, and the filmmakers, concentrating on the moment-to-moment drama of the casting process rather than on back stories or personalities, introduce us to the performers by way of the characters they are hoping to play. Cassie — a role originated by Donna McKechnie, who is interviewed in Every Little Step — is a step away from has-been status and desperate to keep working. Others sing and speak about their childhood love of dancing and one, Paul, delivers a heart-wrenching soliloquy about coming out as a gay man and an artist. The casting of this part is one of the most touching and least suspenseful moments in the film, thanks to Jason Tam’s tour de force audition. As a general rule, if you reduce an entire casting committee to tears, you’ll probably get the part.

Not that every decision is so easy. Among those casting the new production are Bob Avian, who choreographed the earlier show along with Bennett, and Baayork Lee, a fellow choreographer who originated the role of Connie, a tiny dancer with big desires. They and their colleagues survey the contenders with a mixture of compassion and rigor that quietly underscores the wised-up romanticism of A Chorus Line.

The musical, whose rich history is recalled between auditions for the revival, has become such a touchstone because it perfectly captures both the cruelty and the marvelousness of life in the theater. Bennett, who died in 1987, appears in archival clips looking like a slightly jaded elf, combining a weary knowingness with an ardent capacity for wonder.

There is a superficial resemblance between Every Little Step (and, for that matter, A Chorus Line itself) and television reality shows in which ordinary people use their talents to scramble for the spotlight. But those programs are spectacles of amateurism chasing after celebrity, an impulse that could not be further from what Stern and Del Deo, taking their cues from Bennett, set out to honor. The 17 members of that chorus line — and the thousands like them, including those who dream of playing them — are professionals, and one of the names they give to the glory they seek is work. The other is love.

****Every Little Step

Featuring: Donna McKechnie, Jason Tam.

Rated: PG-13, contains adult themes.