Theater

Britney Spears and Natalie Portman battled for an off-B’way role in ‘92

Once upon a time, in a bizarro universe, Natalie Portman and Britney Spears were in the same show. The time was 1992, the universe was off-Broadway and the show was “Ruthless!,” about a girl who’d literally kill for the lead in her school play.

Believe it or not, Spears and Portman — then Natalie Hershlag — were the understudies. Laura Bell Bundy, who went on to Broadway’s “Legally Blonde,” played the murderous Tina Denmark.

“Ruthless!” itself has endured, a campy farce whose edge has been sharpened, bookwriter/ lyricist Joel Paley says, in the age of “Toddlers & Tiaras.” It’s back now for a limited run, and Paley and composer Marvin Laird still remember how hard it was the first time around to find the perfect pint-size triple threat: a singing, dancing girl who could also play a murderer.

Current “Ruthless!” star Sofia Anne Caruso is ruthless in real life, too.Jessica Fallon Gordon for BroadwayWorld.com

Bundy, a 10-year-old from Kentucky, could do it all. But she needed an understudy. “We thought, ‘We’re never going to find another [girl] — we’re really screwed,’ ” Paley recalls. “And that’s when we found Britney Spears.”

Britney, then 10, had it all, he says: “singing, dancing, acting, [plus] confidence and a great mom.” When Laird played the number “Born To Entertain,” young Britney told him to take it up a full tone before belting it out even higher.

“Although they were both nice kids,” Paley says of Bundy and the future pop star, “we saw a chillingly accurate understanding of the drive and passion and ruthlessness that was needed to play Tina.”

After eight months, Spears got antsy. “Even though the part was fun, the process of doing the same thing night after night wasn’t,” she wrote in her 2000 autobiography, “Britney Spears’ Heart to Heart.” After she left, Portman came on board.

Bundy remembers watching her audition. “The other girls were superpolished and pageant-y, and Natalie had this very long hair, down to her butt. There was something real about her.”

The two became fast friends. “We had sleepovers and prank-called people,” Bundy says, laughing. “She was a vegetarian even then. We were at a restaurant and she’d be telling me these horror stories about chickens — she’d be eating a Caprese salad while I was eating prime rib.”

“Ruthless!” has always attracted talented girls with an edge. It seems 12-year-old Sophia Anne Caruso, the new Tina, will fit right in.

She wrote the show’s creators about a “Ruthless!” production she did in Spokane, Wash., and how, making her entrance, she couldn’t open the door — just as the actor on the other side had a heart attack and died onstage.

“ ‘It was the worst thing that ever happened to me and I’ll never get over it,’ ” Paley says, paraphrasing her letter. “ ‘In the meantime, I know all the songs, all the lines, so if you ever do the show again, give me a call.’ ”

It’ll be interesting to see where she is 20 years from now.

“Ruthless!” runs through Sept. 22 at the Triad, 158 W. 72nd St.; tickets, $35 to $45, at 800-838-3000.