Marvel 'Black Widow' spin-off in the works

Marvel Studios are developing a movie based on Scarlett Johansson's Black Widow character.

The 29-year-old actress first portrayed the popular Marvel comic book character - who is also known as Natasha Romanoff - in 2010's 'Iron Man 2' before reprising her role in 2012's 'The Avengers', and is once again set to hit the big screen as the superhero in 'Captain America 2: The Winter Soldier' and 'The Avengers 2: Age of Ultron'.