The standout gowns at last night's The Impossible premiere in LA could be summed up in three words: Old Hollywood glamour. Naomi Watts channeled a modern-day Veronica Lake in a purple petal-printed Zac Posen bias-cut gown, which, in true bombshell form, hugged every curve to perfection. Her retro up-do, costume-inspired drop earrings, and daring open-back cutout (believe us on this one) put the final touches on her elegantly styled old-school ensemble. As for her chic challenger? Petra Nemcova stepped out in a coral-hued strapless Notte by Marchesa number that evoked more of a Rita Hayworth kind of sex appeal than Naomi's less-is-more approach. To complete her look, she wore diamond earrings and crystal-encrusted sandals and carried a bronze satin clutch. With two stunning gowns at the helm and a similar brand of siren glamour at play, it's time for you to decide who gets the best-dressed honors.