It's one of those funny movie "what-ifs". After so many appearances and so much character development, it's hard to imagine anyone other than Johansson in the Natasha Romanoff role. The image of her in the black jumpsuit has become iconic in a very short space of time. But the role was almost played by Emily Blunt. And this wasn't just an "expressed interest" situation. Blunt was cast in Iron Man 2 (Black Widow's first appearance in the MCU) before dropping out due to scheduling conflicts with Gulliver's Travellers (which surely didn't make her anywhere near the money the Widow role would have). Other actresses were reportedly considered before the studio settled on Johansson, including Natalie Portman and Angelina Jolie. Eliza Dushku, known for other Joss Whedon projects like Buffy The Vampire Slayer and Dollhouse, campaigned for the part but ultimately lost out.