Screen writer and director Joss Whedon has revealed that he sees Avengers 2 as a "glorious challenge".

Whedon is currently working on the follow-up to last year’s hugely successful superhero movie, Avenger Assemble, and admits while he is hoping to make the sequel "different", he is aware that it may not be as successful as the first movie.

Speaking to Total Film magazine Whedon said: ''I am not going to try and match the box office of the first one because that would be bonkers. There is a certain level of safety - because now people know about The Avengers and they like the characters so it probably won't completely crash and burn.

''But you don't want to just get by and do something that is merely okay. If I am going to dedicate three years of my short life to this then I want to do something that I have never done before.

''So I think of The Avengers 2 as a glorious challenge - it is a sequel, yes, but how can it be different?''

Returning stars from the first instalment are said to be Chris Hemsworth as Thor, Robert Downey Jr. as Iron Man, Scarlett Johansson as Black Widow, Jeremy Renner as Hawkeye, Samuel L. Jackson as Nick Fury and Chris Evans as Captain America.