A stand-alone Marvel film focusing on Scarlett Johansson's Black Widow character is a no-brainer, according to the Captain America movie directors.

Anthony and Joe Russo, who took charge of 2014's Captain America: The Winter Soldier and the new Captain America: Civil War, were asked about the possibility of the Marvel assassin, real name Natasha Romanoff, getting her own spin-off movie.

"I don't think (it'll take) much," Joe Russo told Collider. "I think it's just a function of where on the slate it goes. She's a bada**."

Black Widow, who is part of The Avengers, has featured extensively across all Marvel superhero films, including Iron Man 2 and the two most recent Captain America films.

Her next outing will be in the two Avengers: Infinity War movies - both directed by the Russo brothers - with Part 1 slated for release in 2018. And the brothers hope that their working relationship with Marvel will continue after Infinity War.

"Our experience with Marvel has been amazing and we really do feel like we're in our creative sweet spot there. So it's definitely a place we'll always think about," Anthony said.

"One of the great things about Marvel is that they like to marry genre, and who knows where it's going to go from here," Joe added. "I think there are going to be some fun surprises in store over the next few years."

Marvel Studios boss Kevin Feige also raised hopes for a Black Widow movie last month (Apr16), but admitted it would take a few years before it's released.

"Yes, for sure, I think (Black) Widow at some point would be great," he said, before insisting it would be some time before that idea could even be developed.