BY DARLENE DONLOE

CONTRIBUTING WRITER

Syesha Mercado and Adrienne Warren are not big names in the theater world, but they are playing big roles in a big show and it’s a big deal.

They are “Dreamgirls.”

The legendary 1981 musical, which originally starred Jennifer Holliday, Sheryl Lee Ralph and Loretta Devine, is currently playing at the Ahmanson Theatre in Los Angeles through April 4.

Mercado was standing outside of Radio City Music Hall when she got the call that she had scored the role of Deena. She had been waiting all night to hear the news. She couldn’t sleep.

When she finally got the call, she jumped up and down with excitement. After all, this was her first big show. The woman who had wanted to be a performer ever since she was a child could hardly contain herself.

“It was like a dream come true,” said Mercado, who admitted she had never seen any of the touring productions of the show before landing the role. “This was all very new to me.”

It was also, admittedly, a long, stressful process, but worth every drop of sweat, according to Mercado.

“I had undergone a six-month-long audition process that had me flying back and forth from coast to coast to sing different songs and read different scenes,” said Mercado, the second runner up on the seventh season of “American Idol.” “There was even an agonizing two-month period when I didn’t hear anything.”

Warren wasn’t standing outside Radio City Music Hall when she received word she would be playing Lorrell in the show. But she was also enthusiastic. She too considered it a “dream come true” — even though she had already appeared in the ensemble of the 25th anniversary of “Dreamgirls,” starring Jennifer Holliday, in 2007.

“I think what makes this show great is you can identify with just about any of these characters,” Warren said. “I identify with her (Lorrell) because of her passion for music.”

“Dreamgirls” is the story of a 1960s female singing group out of Chicago, who go from wannabes to superstars in meteoric fashion, learning life’s lessons along the way.

Fame, success, betrayal, abandonment, greed, love, hate, disappointment and even death become part of their rites of passage.

Mercado, 23, who studied theater at Florida International University, and Warren, 22, a recent graduate of Marymount Manhattan College who minored in musical theater before going on to rack up theater credits such as “The Wiz,” “Cats” and “Big River,” belie their young years. They talk like seasoned pros when it comes to their expectations of the show, this business and their futures in it.

“I love theater because it’s not predictable,” said Warren, who is originally from Virginia. “Things can happen on stage and off stage. It’s a challenge. But, that’s what makes it fun. Doing eight shows a week isn’t easy. But, it allows you to grow as a performer and a person. Your show off stage is just as important as the one on stage. The show must go on!”

The fact that many will compare this current show to the original and other subsequent touring companies, as well as the movie, hasn’t escaped Mercado or Warren.

“I kind of told myself certain things come with the territory regarding the comparison,” said Mercado, who is currently working on her first CD, collaborating with Grammy-winner Diane Warren and Evan Bogart. “I was intimidated at first. There was pressure from those who hired me, my cast mates and my family. They all wanted me to do well. Once we got to the Apollo and started doing tech rehearsals, it all went away and I started enjoying it. I always try to think positive. I learned to come into my own.”

Warren agrees.

“We’re going to be compared regardless,” Warren said. “I faced up to that. I think all of us have faced up to that. I can only be me. I can’t be Anika (Noni Rose). I have to be me. Every time we walk on the stage there are people who are supporting us and there are people waiting for us to mess this up.

“If I touch one person in the audience — that’s enough for me. I can’t impress everyone.”

“Dreamgirls,” directed and choreographed by Robert Longbottom, stars Mercado (Deena Jones), Warren (Lorrell Robinson), Margaret Hoffman (Michelle Morris), Moya Angela (Effie White) and several others.

Showtime information:

“Dreamgirls,” the Ahmanson Theatre, 135 N. Grand Ave., Los Angeles; 8 p.m. Tuesday through Friday; 2 and 8 p.m. Friday through Saturday; 1 and 6:30 p.m. Sunday; no performances on Mondays.

Running time: two hours, 30 minutes. Ticket prices: $20 to $95. Information: (213) 972-4400, www. centertheatregroup.org.