Ang Lee’s 2003 portrayal of Stan Lee’s Dr Bruce Banner , played by Eric Bana, bombed at the box office while gaining a small cult following, while Edward Norton’s 2007 film The Incredible Hulk fared little better. Norton was infamously dropped from reprising the role in the Avengers film, to be replaced by Ruffalo.

Feige previously ruled out any more spin-offs from The Avengers – with Thor and Captain America heading-up their own movies to muted box office reactions over the last couple of years – but Ruffalo’s lighter, more comedic take on Hulk was regarded as a highlight of Avengers Assemble. 

Feige said: “Do I think Hulk can carry a movie and be as entertaining as he was in Avengers? I believe he absolutely could.

“We certainly are not even going to attempt that until Avengers 2, so there’s a lot of time to think about it. I don’t think there’s a lot that we couldn’t do someday.”

Ruffalo recently revealed he has signed a six-film deal with Marvel and is said to be keen to pursue a solo movie, while rumours are surfacing that Avengers Assemble director Josh Whedon will be approached to direct.

“I think the pathos and humour, most importantly, that Mark and Joss [Whedon] brought to it showcased a different element of Hulk that’s there in the comics, and was always inherent in his character,” Feige said.

“But when he was so brooding in his other two films, he didn’t get to have that wry sense of humour that Mark did such an amazing job performing.”

Whedon is set to return to the director’s chair for Avengers 2, to be released in May 2015.