Doing the Two-Step, Double-Time : Dance: Miami Ballet’s two sets of twins to give new meaning to pas de deux in Costa Mesa.

Miami City Ballet could be a battleground for the mother of all sibling rivalries: The troupe has not one, but two sets of identical twins. Imagine the sparks at casting time. . . .

But Laurel and Amy Foster consider themselves best friends. Maribel and Mabel Modrono get along famously.

“We always work like a team,” said Laurel Foster.

“If one twin’s unhappy,” Mabel Modrono said, “the other one’s unhappy.”

Celebrating its 10th anniversary, the 35-member Florida-based company will dance Friday through Sunday at the Orange County Performing Arts Center in Costa Mesa. It’s the second half of a split dual engagement (with the Pacific Northwest Ballet, which visited in June) replacing the Joffrey Ballet’s aborted center appearance.

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Each night’s mixed bill will include two works by Peruvian-born resident choreographer Jimmy Gamonet de los Heros: the tango-inspired “Transtangos” (to Astor Piazzolla’s sultry rhythms) and “Nous Sommes,” an acrobatic love duet. George Balanchine’s “The Four Temperaments” and “Western Symphony” complete the programs.

Company founder and artistic director Edward Villella was the firebrand star of Balanchine’s New York City Ballet in the 1960s and ‘70s, and Balanchine’s neoclassic compositions make up almost half of Miami City’s repertory.

Troupe principals danced such works “as if the choreographies were brand-new, created especially for them,” wrote The Times’ dance writer Lewis Segal last year when the troupe performed at Los Angeles’ Wiltern Theatre.

During recent phone interviews from Miami, both sets of twins--four bubbly women, each prone to finishing her sister’s sentences--discussed how demanding careers haven’t derailed the camaraderie they’ve always enjoyed.

The Fosters, 22-year-old corps members who joined the troupe in 1992, were born and raised in Atlanta and trained at the School of American Ballet, NYCB’s academy.

“We’ve always been interested in the same things,” Laurel said. “We started [professionally] doing a little acting in children’s theater, then we got into ballet, and our [first] teacher was very strict. She only wanted you if you cared and had the mind to do it, and both of us were really dedicated, and we worked really hard.”

Both sets of twins concur with company members who say that the Fosters look and dance more alike than the Modronos, both principal dancers. But that similarity--and the potential for anonymity onstage--doesn’t bother the Fosters, who will appear in “The Four Temperaments.”

“My face is longer and more oval-shaped,” Laurel said. “Amy’s is more round, and that’s the way people tell us apart.”

But, said Amy, “our bodies are so similar, we’ve had the same training, and we know how each other’s moves, so when we’re put in the same ballet, where there are two girls and a boy, for instance, my sister and I can do the same style and syncopate.”

“It’s like we are bookends,” Laurel said, “which is really nice, because sometimes two people dancing very similarly makes it look that much better.”

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Individuality, onstage and off, is important, of course.

“We like to be very different,” Amy said. “We dress differently; we have our own distinct personalities, and we prefer for people to call us by our names rather than ‘the twins.’ ”

But the sisters, who often assume the same role in different performances, said that the only reason they prefer to learn different parts is so that they can dance at the same time.

“This past year,” Amy said, “we learned the same part in [Balanchine’s] ‘Who Cares,’ and we were thinking that it would have been so nice to learn different spots so we could dance together out there. It’s such a fun ballet; it would have been so much fun to do it together.”

What if only one Foster were promoted to principal, for instance? Not a worry.

“If something good happens for one of the sisters,” Amy said, “the next year it’ll probably happen to the other one.”

The Cuban-born, Miami-bred Modronos (who are slightly older than the Fosters but won’t give their age) joined Miami City in 1988 after dancing with the Ft. Worth Ballet in Texas. They also trained at the School of American Ballet, but assert that they differ in technique and stylistic approach, Maribel more “lyrical,” Mabel more “aggressive.”

“If we want to, we can dance exactly alike,” said Maribel, who will appear in “Western Symphony.” “But [the differences] have made us even closer. For instance, Mabel may have things that are very [technically] easy for her and very difficult for me, so she helps me, or vise versa. We’re both very competitive, but we help each other. It’s very healthy.”

“I learn from Maribel,” said Mabel, who will appear in both Balanchine ballets. “She’s always been more lyrical than I have, and she’s a natural turner, since we were young. I was always the more daring one.”

These sisters bonded as youths when they began to take advantage of their looks by playing pranks--such as switching dates on prom night. They can’t get away with much today--at least nothing they’ll talk about on the record--but they kept up the shenanigans as long as possible.

“In variations class,” Mabel said, in which students execute solos from famous ballets, “I’d do the variation, then if Maribel wasn’t in the mood, I’d go and do it again, pretending I was her. They never caught us, never. I’d dance exactly the same, but the teachers at SAB, I can’t mention any names, but they were older, so they didn’t know. Even the young ones had a hard time telling us apart.”

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The Modronos have developed a warm relationship with the Fosters.

“It’s not every day that you work with another set of twins,” Maribel said, “so when they first joined the company we had these moments we’d call ‘twin talk.’ We’d compare stories or feelings, like when one twin finds a boyfriend and the other is on her own. You have to find out how each other feels because you have to let go.”

At Miami City, Mabel was cast in principal roles before Maribel. But the strength of their relationship carried them over the hump.

“We’re both so determined and constantly supporting one another,” Maribel said, “which helps us through those difficult moments. And, in the long run, it has balanced out. It all comes together in the end.”

* Miami City Ballet opens Friday at the Orange County Performing Arts Center, 600 Town Center Drive, Costa Mesa. 8 p.m. Through Sunday $18 to $55. (714) 556-2787.