Robert Downey Jr reckons that Marvel should shoot a solo Black Widow movie.

The Iron Man star, whose character featured alongside Black Widow in Avengers Assemble, is backing the idea of a standalone film for Scarlett Johansson's character

Momentum has gathered since her expanded role in Captain America: The Winter Soldier, with Marvel Studios' hesitation adding to a wider debate about the lack of female superheroes in cinema.

"Doesn't Scarlett deserve a break?" Downey Jr said to USA Today, before admitting that it would be "appropriate" for her to lead her own film given the success of her recent projects at the box office.

"I think that the interesting thing particularly after Guardians with Zoe [Saldana, or] even from the first Iron Man where Pepper was kind of this really - to me the Iron Man franchise would never have taken off without [Gwyneth] Paltrow.

"There's something about her that grounded the story. She's not your typical lady in a superhero movie, and then by Iron Man 3 she's swallowing serums and putting on suits and kicking [butt] and all that stuff.

"But it would be kind of more appropriate for a character that already was like a Black Widow [to lead a movie]. It just seems like whatever Scarlett does, people want to go see it."