Emily Blunt has emerged as the frontrunner to play Natasha Romanoff in the “Iron Man” sequel. She’s a Soviet superspy who doubles as Black Widow, a beauty in a skintight black costume enhanced by high-tech weaponry.

Blunt, whose credits include “The Devil Wears Prada,” “The Jane Austen Book Club” and “Charlie Wilson’s War,” will get a profile boost when she stars with Benicio Del Toro in the Joe Johnston-directed “The Wolf Man” for Universal.

Marvel would not comment on the Black Widow casting. The Justin Theroux-scripted “Iron Man 2” will begin production in the spring for release by Paramount in summer 2010.