Backstage on Broadway, the hour before curtain is a bustling time. Performers are coming in, dinner deliveries are arriving at the stage door, makeup, hairdressing and costume people are making their rounds.

At the Shubert Theatre before a recent preview of "Monty Python's Spamalot," all of that was going on, but it felt a little different from other productions. There was a sense of added energy, of positive hubbub.

"Everyone wants to do something with this show," said a slightly frazzled but happy press agent as she bounced between one reporter waiting to interview an actress and another writing a story about the props.

With an advance sale north of $16 million and avid anticipation, "Spamalot" is, pre-opening at least, THE show of the 2004-05 Broadway season.

This is nice, of course, for the show's well-known stars, David Hyde Pierce, Tim Curry and Hank Azaria, its well-known creator, Pythoner Eric Idle, and its well-known director, Mike Nichols. But it's extra-special-nice-with-whipped-cream-on-top for the little-known Sara (pronounced Sah-rrra, with rolled R's) Ramirez, an actress on the verge of the breakthrough every performer dreams about.

It's not just that Ramirez has the good fortune to be the lone - and very attractive - female principal in the show. There are also the reviews she received during the pre-Broadway Chicago run: "For sheer star power, there is Sara Ramirez, with her voluptuous figure and a gargantuan voice that moves from opera to jazz ... with stunning ease," and "Sara Ramirez ... remember that name. She won't be unknown for long. This Ramirez kid has the stuff to go all the way."

Sitting, pre-show, in her cramped dressing room, wearing a pink flannel robe and pink slippers, no makeup, dark hair hanging casually - the whole effect suggesting a sweetly pretty girl next door - Ramirez seemed suspiciously calm about her anticipated leap into fame.

"Look, I have an ego like anyone else," she said, smiling. "But I know that I have to focus on the work. I've learned not to have expectations. That can throw you. Everyone was excited about 'Capeman,' and we all know what happened with that."

That was seven years ago, when Ramirez had just graduated with a degree in drama from Juilliard. Getting a role in Paul Simon's highly anticipated musical must have seemed to her the kind of enormous break that being in "Spamalot" does now. But "The Capeman" became one of the biggest flops in Broadway musical history.

If Ramirez won't think, or at least talk, about what life might become for her after "Spamalot" opens Thursday night, she did admit she's excited being in the high-profile show.

"Glenn Close came backstage," she said. "That was something. And John McEnroe was there one night. It's all been great."

The 29-year-old Ramirez has worked hard for this opportunity, not always with the best luck.

After "The Capeman" there were two other Broadway musicals, "The Gershwins' Fascinating Rhythm" and "A Class Act." Although Ramirez, with her tall, statuesque figure and a remarkable voice that seemed to bound across octaves, stood out, neither show was around long enough for her to be widely noticed.

There was other stage work, including workshops; New York-based TV - with a stint on "As the World Turns" - and some small film parts. But by 2003, she said, she felt stymied.

"I was going on auditions, but nothing was really happening for me," she said. "I felt it was time for me to go to L.A.; they say you know when it's time. I'd been auditioning for pilots in New York, but you do it on tape. I wanted to go out there and meet the casting directors and audition in person."

She moved to California and got a role in a comedy pilot, but it didn't sell. When she returned to New York last spring for a week's visit, her agent suggested she try out for a show. It was "Spamalot."

"I just auditioned like anyone else," she said. "It was in the theater itself, which was very old school, very classy. Mike Nichols sat in the front row with a couple of other people. I sang a number, and I left. I didn't think much about it. But then I got a callback, and there were around 20 people there, and I thought, 'These must be the producers.' I sang the same song, and an hour later they told me I had the job."

John Du Prez, who wrote the show's songs with Idle, has said that Ramirez's voice bowled everyone over. "You often have a choice between a contralto and a soprano," he said. "She has both. And she can act."

Ramirez, who plays the Lady of the Lake in the show's mock Arthurian plot, said she's had to locate her antic side to fit the show's spoofy mood, but that it hasn't been hard.

"Everyone's been incredibly helpful," she said, mentioning her nurturing comic co-stars, and Nichols, as well.

"He's a very genuine and caring director. He's really trusted me a lot [to find her way into her performance]. A lot of the comedy I do is in my singing."

Idle, she said, has been a very calming presence.

"I might be sitting there concerned about something, and he'll come by and say, "You're fine, you're fine. Don't take everything so seriously.'Ÿ"

Ramirez was born in Mexico and moved to San Diego as a child with her Mexican-American mother after her parents divorced. From the fourth through 12th grades, she attended a performing arts school, even though, she said, her ambition was to be an engineer.

"When I was 16, I was in a school production of 'A Chorus Line.' I sang 'What I Did for Love' and my mother was in the audience, and I think that's when I decided I wanted to be in show business."

If becoming a star was a fairy tale then, it's on the verge of becoming a true story.

E-mail: feldberg@northjersey.com