Scarlett Johansson worked her ass off – literally, depending on your opinion – for her role as the Black Widow in “Iron Man 2.” I’ve complained in a few articles that she lost all of her beautiful curves, which to me are a big part of what sets her apart from most other actresses. But Scarlett quickly pointed out to the media that she lost weight and toned up for her role, not due to chronic Hollywood pressure. According to Jon Favreau, the film’s director, Scarlett did it with a low carb diet.

Even enviable-looking Scarlett Johansson couldn’t disguise her fear at having to don a skintight catsuit for her Iron Man 2 role as the Russian spy Black Widow.

“I kicked some major butt,” the actress, 24, told PEOPLE at Comic-Con of her training regimen to make her a shapely superhero ready for acrobatic battle scenes. “It was many, many, hours, days, and months of stunt training and strength training, but it’s fun because I had a goal. The goal was the Lycra catsuit.”

Was she happy with the results? “Finally I was, yes,” she said with a laugh. “You put that much work into something and you put it on and you better be happy with it.”

When it came to putting on the catsuit, “It was crazy to see it for the first time – everything all zipped up and all the weapons in there, bracelets on, the whole look. It was pretty sweet, I have to say,” she says.

As for the impression it made, “Certainly walking on set, because a lot of the people that worked on the film were fans of the comic and of course they knew the Black Widow – they were all super excited to see the Black Widow,” she says. “When everybody in the crew were like, ‘That looks awesome!’ I knew. Like, ‘Okay.’ ”

“She was wearing an unforgiving costume,” concurred Johansson’s Iron Man 2 director Jon Favreau, who was impressed by his star’s physical commitment to the role. “She didn’t eat much, that’s for sure. She likes food, as do I, and she was definitely on a low-carb diet and training very hard. It was amazing.”

After viewing Johansson’s stunt work, Favreau says, “I think people are going to be very impressed when they see her. It’s totally different than anything you’ve seen her do before.”

[From People]

Before people go off on Scarlett about a low carb diet, keep in mind Jon didn’t say she was doing the Atkins diet. They’re not the same thing. There are all sorts of low carb and modified carb diets that are not bacon and butter based. I’m a big fan. Well, not a big fan of doing them, but I’m a big fan of the results. I can’t deny the Scarlett looks great; I just loved how she looked before. I can’t think of many actresses who could rock curves the way she could. I can’t help but hope she relaxes a bit and goes back to her natural shape. She’s gorgeous either way, but I’m a fan of the more realistic look.

Here’s Scarlett at the LA Shorts Fest opening night on July 23rd. Images thanks to WENN.com .