Scarlett Johansson says 'The Avengers' sequel is even more ''complex'' than the first film.

The actress is returning as Marvel character the Black Widow in the superhero team-up movie, 'Avengers: Age of Ultron' next year, and hinted Joss Whedon's movie is likely to be one of his best yet.

She teased: ''Joss Whedon, who is coming back for 'Avengers 2', has got his finger prints all over that project, certainly just as much as he did with 'Avengers', if not even more. He's in a place now where most directors would be extremely burdened by the task of having to top the last one.

''But for some reason, I think the universe is working in the right way for him. Joss seems extremely focused and he's in some ways less jaded. He really is in a good place to start this movie.

''He's crafted an even more complex and cerebral story this time around while still giving the fans those superhero elements that they love, the little Easter eggs, the explosions and the surprises, the little wink to the audience. He's got a very dry sense of humour as a person and as a writer. ''

Johansson is confident fans of the franchise won't be disappointed with the results thanks to Whedon's ''exciting'' script.

She added in an interview with French website AlloCiné: ''The irony is not lost on him. These characters are still in a completely bizarre set of circumstances, they're totally aware of what a strange team of misfits they are. It's pretty exciting I think the fans will not be disappointed. Unless we mess it up, which is always a possibility!''