It’s a cutthroat world for performers of musical theater, where rejection is often just another audition away. That’s the way it is for the characters in “A Chorus Line,” and likely will be for the students playing them after graduation.

Jet Thomason knows that world. The OU alumnus graduated in 2002 and moved to New York where he was thrust into the world of trying to make it in the big city, and he did just that.

Now, Thomason is back to star in “A Chorus Line,” the Pulitzer Prize- and Tony Award-winning musical, opening tonight in the Rupel J. Jones Theatre.

It’s the first time an alumnus of the department has returned to play a role in a University Theatre production. Thomason is taking on the lead role of Zach, the imposing director who holds the keys to each chorus hopeful’s success or failure.

Thomason’s experience with a wide array of personalities helped inform how he would play the character, he said.

“I’ve taken a little bit of all the interesting directors I’ve worked with, both consciously and subconsciously,” Thomason said. “I’ve met plenty of Zachs in my life.”

Directors are inherently intimidating because of the power they hold, so he felt little need to play up that side of Zach, Thomason said. Rather than pursue the blustering, “ridiculous” characterization of Zach that Michael Douglas made famous in the film adaptation, he wanted to find more heart in the character.

After all, this is a man who’s trying to do his job while battling with romantic feelings for one of the auditioning actresses — Cassie, a former flame Zach believes is far too talented to be stuck in the chorus.

The show also details the complex relationships between fellow actors auditioning for the same show, he said. You have to bond and compete at the same time.

“It’s trying to find the delicate balance between friend and enemy,” Thomason said. “It’s an emotional journey.”

Even though Zach spends much of the time not even visible — just a booming, commanding voice — Thomason wanted to emphasize the humanity of the character.

“A lot of times people play it like a voice,” he said. “I think he’s more than just a voice.”

Thomason’s voice and stage presence were part of the equation that director Lyn Cramer was looking to fit, she said, and the gap in age and experience between Thomason and the undergraduates gives Zach a noticeable authority.

Thomason played the lead in the very first show Cramer directed for OU, but he graduated immediately thereafter, she said.

“He was a doll when I worked with him, but I barely knew him,” Cramer said.

Thomason arrived in Oklahoma six weeks into the rehearsal process — a far more grueling regimen than most productions at OU these days, Cramer said — and helped give the show a push that doesn’t usually come until right before the show opens.

“He gave us a shot in the arm that was really helpful to everyone,” Cramer said. “[This show] is a huge math project — it’s intricate, each dancer to one another.”

Having Thomason at the university presents an opportunity for current students to be inspired, and to benefit from the knowledge and life experience that he has acquired, Cramer said.

In addition to performing in “A Chorus Line,” Thomason also presented to seniors in the department a documentary series he created that details the ins and outs of the theater industry in New York.

But Thomason also has received from the students he’s surrounded with.

“I’ve watched Jet be in awe of our students,” Cramer said.

Thomason sees a marked difference from when he was a student, he said.

“Compared to when I was here, the talent pool is deep,” Thomason said. “[And the college] is definitely preparing them better for the professional world. There’s less of a transition now from OU to the real world.”

Audiences for “A Chorus Line” will see actors and characters on that cusp, and fans of classic musical theater dancing will find no shortage of it.

“Audiences that come to musicals want to see dance,” Cramer said. “[This show] is nothing but dance from start to finish.”