Scarlett Johansson says 'Avengers: Age of Ultron' is a ''continuation'' of 2012's hit film.

The actress plays Black Widow, aka Natasha Romanoff in the films, and has revealed the characters grow whereby the are able to take the ''next step'' in the forthcoming Marvel picture, which is due for a May 2015 release.

She told ''I mean this movie feels like the continuation of 'The Avengers', it doesn't feel like a tag-on or the rehashed version or just 'let's throw a bunch of new characters in there and keep the thing alive.' It really feels like the next step, and all of our characters, our relationships with one another continue to progress, become more intertwined, more complicated, more meshed.''

Johansson also gushed about director Joss Whedon who has come up with a ''totally solid'' and ''ever-expanding Marvel universe''.

She explained: ''I was just amazed -- Joss is something else, he really is. He locks himself away for God knows how long, I think he has the dark circles to prove it. [He] just came out with something totally solid. I was really impressed by his ability to make this ever-expanding Marvel universe feel very close-knit and cerebral and progressive.''

Johansson is hoping fans of the comic will ''love'' the film's ''dramatic moments'' which the viewers can relate to.

The star added: ''And the film has a lot of great comic book moments that the fans are gonna love, but it's also got a lot of really great dramatic moments that audience members, I think, will really relate to.''