Based on a novel by Audrey Niffenegger, the movie stars Rachel McAdams and Eric Bana as a loving couple plagued by his uncontrollable time traveling—it’s a genetic condition, naturally.

The movie also has three child stars, who arrived first to the Wednesday, August 12 screening at the Ziegfield Theater. Preternaturally poised, already pros at posing in front of the posters and giving diplomatic answers, they had tiny French manicures and carried touch-up lip gloss in their purses.

The improbably named Brooklynn Proulx (related to Brokeback Mountain author Annie Proulx, a rep was pretty sure), age ten, played Ms. McAdams’s character as a child. She reported that one of her favorite parts of filming was having fake teeth made in order to look older. Several reporters playfully asked Ms. Proulx where in time she would like to travel. Each time she replied that she would like to go back to the set of her first movie, “to see how I’ve grown.”

Director Robert Schwentke took a similar approach to Ms. Proulx’s when confronted with the inevitable time-travel question: he would like to go back to the first day of shooting, “knowing everything I know now.”

Executive producer Brad Pitt made a surprise appearance, rushing past the press line in a blur of bushy goatee.

Ron Livingston, who plays the loyal-friend character Gomez, said he hardly counted as a token minority. Gomez was short for a long Polish name, he explained. Ah, yes.

Despite the muggy weather, a mass of fans had congregated across the street, holding rolled-up movie posters and yelling—for unknown singer Erika Jayne, improbably; for Rachel, ardently; for Eric; and, hysterically, for Brad. Alas, nobody yelled for Ron.

The red carpet’s row of movie posters created a long arcade of Rachel McAdamses, all looking lovelorn/bored. The actress herself, however, was achingly cute and irrepressibly charming, chatting and gesticulating even as flacks hustled her along. She wore a draped white dress with shoulder pads and a great swath of exposed chest.

Mr. Bana wore a three-piece suit. He fanned himself with an envelope, and turned around to discreetly swab sweat whenever possible.

It had been the summer of Bana, fawned a radio reporter—Star Trek, Funny People, now Time Traveler?

“Actually, it’s been my winter,” replied Mr. Bana, who is Australian. No time travel required!