04/24/2012 at 08:00 AM EDT
Reprising her role as the butt-kicking Black Widow in The Avengers
, Scarlett Johansson
had her own butt to worry about. Namely, how it looked in her skin-tight, curve-hugging costume.
"First of all, every woman has body worries. I'm not exempt from that," she tells ITV1's Daybreak
morning show in the U.K. on Tuesday.
"But beyond part of the by-product of spending that much time in the gym is that you can fit into a cat suit."
But those workouts weren't all about her hot bod. Johansson, 27, who's promoting the latest installment
of the superhero franchise, in theaters May 4, says she performed her own stunts in the movie as she worked with stunt-double Heidi Moneymaker, which was "a lot of training and dedication."
"It hurts and it hurts and then suddenly it doesn't hurt," she says. "And you're getting it right, and it's a great moment – you feel like you've accomplished something big."
Next up: The actress, whose relationship
with New York-based advertising executive Nate Naylor was revealed
in January, might just make her way from the gym to the recording studio again.
"I would love to," says Johansson of a potential music-career resurrection, four years after releasing her debut album
. "Releasing an album is like a little baby, and you just have to nourish it and you need time for it."