Before watching auditions and elimination rounds and hearing personal confessions became a national prime time pastime with shows like “American Idol,” “America’s Next Top Model” or “Project Runway,” there was a musical without a plot that focused on the lives, hopes, dreams and fears of a group of auditioning dancers — “A Chorus Line.”

The national touring production of “A Chorus Line” has taken up residence at the Ahmanson. We don’t get to see Mario Lopez of “Dancing with the Stars” fame. He’s in the New York Broadway cast. Yet this ensemble is wonderful, giving the music and lyrics a life that will endure in people’s imaginations long after they leave the theater.

This 1975 musical won a Pulitzer Prize for Drama — unusual for a musical — and nine Tony Awards, including Best Musical, Best Book and Best Score. Marvin Hamlisch composed the music and Edward Kleban supplied the lyrics while James Kirkwood and Nicholas Dante wrote the book, which was based on taped workshops with Broadway dancers, some of whom would later appear in the original cast.

As the story goes, Zach (Michael Gruber) and his assistant choreographer Larry (John Carroll) are auditioning dancers for an upcoming Broadway production. We see the dancers repeating the same routines, some already rattled, not picking up the combination of steps quickly enough, and soon only 17 remain. Zach will ultimately pick only four men and four women who appear on a stage that is bare and black except for a long white line. From time to time, mirrors descend from above in a semi-circle or upstage, curtains reveal a wall of mirrors.

Zach asks the dancers to tell him about themselves. Mike (Clyde Alves) explains how he followed his sister to her dance classes and found he had a natural talent in “I Could Do That.” The seductively over-confident Sheila (Emily Fletcher) — joined by Bebe (Pilar Millhollen) and Maggie (Hollie Howard) — explains how she escaped a bad family life because everything was beautiful “At the Ballet.”

Kristine (Jessica Latshaw) apologetically reveals she can dance but is tone deaf in “Sing,” as her husband Al (Colt Prattes), also a dancer, prompts, fills in and finishes her sentences. Diana (Gabrielle Ruiz) sings about how acting classes made her feel “Nothing.” There is also one dancer who has a history with Zach, Cassie (Nikki Snelson), whom Zach feels is too good for the chorus.

Gruber is a triple threat — he can act, dance and sing. He actually performed as Mike in the last Broadway version of the original production in 1989-90. Before joining this national tour, he was working on the current Broadway revival, playing the very droll Greg, a role played with aplomb here by Denis Lambert.

The original show was conceived and directed by the late Michael Bennett, who also choreographed with Bob Avian. Avian is back, this time as director, with choreography re-staged by Baayork Lee.