It's no accident that the last names of Laurissa Romain and Luka Kain rhyme, because these two child actors, who play Ngana and Jerome in South Pacific,have had a deep connection from the start. They met five years ago, sealing their friendship at the Diana Ross playground in Central Park, when Laurissa was 5 and Luka was 3. "They were instant buddies," said Luka's mother, Lisa Calli, the other day at the Vivian Beaumont lobby before a matinee. "Laurissa felt like family right away," added Luka.

When it came to auditioning for South Pacific, however, Laurissa and Luka were no brother-and-sister act. "They didn't read together until the fourth, and final, audition," said Laurie Sheppard, interviewed with her daughter at the Beaumont lobby separately from Lisa and Luka. "They saved the best for last," said Luka proudly. Laurissa, slightly more worldly wise, elaborated, "But it wasn't as if Luka and I had worked up a routine."

Laurie reminded her daughter: "You were both wearing blue-and-white that day, just like it turned out that you do in the show."

"That's true," Laurissa admitted, before observing that what she most remembered from the final audition day was getting a Mister Softee and some Pokemon cards at Duane Reade.

Laurissa and Luka were on a playdate just after that crucial audition, during which the news came in that they were being offered the parts. Laurissa and her mom got the call first. "I screamed!" Laurissa admitted, "and I knew that Luka would get the call next. And he did."

To employ some favorite words of Nellie Forbush and Emile de Becque, neither Laurissa nor Luka were bussed in to their New York auditions like hicks from the sticks. Laurie is an actor and Lisa is a talent agent, and both have carefully overseen their children's careers in show biz. Laurissa had her first head shot taken at the age of six months, and appeared frequently on morning television as an infant. ("Kathie Lee kissed my toes when I was 17 months," Laurissa said.)

For his part, Luka is practically the Giselle of the boys' print-ad set. He did his first campaign, for Disney, at the age of one, and has subsequently smiled on cue for Baby Gap, Brooks Brothers, and Lacoste.

For both Laurissa and Luka, however, South Pacific has been the big time, showcasing them in the country's biggest media market, with its attendant exposure and chance to meet celebrities. "I hadn't been really nervous before going onstage since opening night," Laurissa said, "until last weekend, when Hillary Clinton came to a matinee."

"We got our pictures taken with Hillary and the Secret Service," Luka added. "Cool."

What do Laurissa and Luka do backstage when U.S. Senators and their entourages don't happen to show up? "I make cupcakes and bring them to the cast," said Laurissa. "In one performance I almost tripped going down the steps and Jerold [Salomon, who plays James Hayes] caught me. So I made him a cupcake shaped like a life preserver."

Luka added: "Vanessa [Brown, the children's backstage guardian] has been teaching us to draw and to do magic tricks with cards. And Laurissa is teaching me to tap."

"I'm also teaching Paulo to tap," observed Laurissa, referring to her onstage dad, portrayed by Paulo Szot. "I'll teach anyone in the cast who wants to learn."

Since South Pacific looks to have a very long run, Laurissa's line of pupils could stretch longer than the cancellation line before every performance. "Fine with me," she says, before running down the lobby steps to get into the matinee's costume and make-up.

BRENDAN LEMON is the American theater critic for the Financial Timesand the editor of lemonwade.com