Instead of her usual gig instructing students at New York University’s Tisch School on the art of creating a new musical theatre role, Eden Espinosa is across the country writing a page of her own textbook on the subject.

“I took the [spring] semester off,” the Brooklyn and Wicked star says, on a rehearsal break at San Diego’s Old Globe Theatre where she is starring in the world premiere of Rain. “They have a new works program for composers at NYU, and we were going to be working hand in hand with the composers on their new works, figuring out what that relationship entails.”

“We talk about when you can give your ideas and your opinions, how do you bring their vision to life without sacrificing yourself completely? It’s how you originate a role, basically,” she continues. “Oddly enough, it’s what I’m doing here. That’s kind of cool. That realization just happened.”

Espinosa laughs. She’s in high spirits even if the character she is playing is frequently miserable. Featuring a score by Michael John LaChiusa and a book by Sybille Pearson, Rain not only signals Espinosa’s return to musical theatre, it’s her first non-concert performing job in nearly six years.

Following extended runs in the Los Angeles and San Francisco companies of Wicked, Espinosa “stepped away a little bit.” She got married, moved to New York and put out her debut album, “Look Around.”

After her years of Wicked work and being the final Maureen in the first Broadway company of Rent, Espinosa needed to reassess. She enrolled in a two-year acting program through the William Esper Studio and began teaching.

“Things weren’t rolling along like I naively anticipated that they would, and it played a number on me, emotionally and mentally” Espinosa says. “It took a toll on my confidence, and I kind of lost myself for a little bit. I didn’t go to college, so I said, ‘I want to study. I want to hone my craft and have a skill set instead of just resting on my laurels.’”

Her comeback role is the ultimate survivor: Sadie Thompson, a former prostitute on the run from her past, who ends up on a U.S. Marine base in Western Samoa amidst doctors and a zealous missionary. The heroine of a short story by W. Somerset Maugham, Thompson has been brought to life in plays and portrayed in film adaptations by Gloria Swanson, Rita Hayworth and Joan Crawford.

Espinosa considers Sadie the first grownup role of her career, and the decidedly un-pop score by the five-time Tony nominee LaChiusa (Marie Christine, The Wild Party) exercises musical theatre muscles that Espinosa says she has not previously flexed.

“It was probably the first audition of my career where I actually had a good time in the room,” she says. “I was just starting to get back into auditioning again, and so it was sort of a leap of faith that I was taking in myself as an actor just saying, ‘Let’s put into practice what you’ve been learning.’ To be perfectly honest, I walked out of the room not really caring if I got the role or not because it felt so good to just be in there.”

Espinosa stayed clear of any of the film adaptations and didn’t read the short story until rehearsals began. She was told to be aware that in fleshing out the short story, LaChiusa and Pearson brought new psychological depths to the character.

Espinosa’s assessment of this soiled flower? “She’s a badass,” the actress says.

“She’s a fighter, but she’s damaged, and she is incredibly broken inside,” Espinosa says. “She talks the way she wants, and she drinks and smokes. Basically it’s, ‘This is who I am, and you can do with it what you will.’ It’s fun, but it’s a huge emotional roller coaster for me.”