Joss Whedon has revealed Scarlett Johansson was ''word perfect'' in 'Avengers: Age Of Ultron'.

The acclaimed director has heaped praise on the Hollywood icon, who starred as Black Widow/ Natasha Romanov, and Tom Hiddleston - who played Loki - in the Marvel superhero movie that hit cinema screens earlier this year.

He said: ''I'm going to have to give it up for Natasha and Loki, just for being a dream to write, and to two actors for being word perfect and riveting.''

Joss has already confirmed he will not return to direct another movie in the 'Avengers' series, and he's also revealed he doesn't have any plans to create a director's cut of 'Avengers: Age Of Ultron'.

He told Collider: ''It has always been my ambition never to do a director's cut of anything, and always to make the movie with the studio that we both want to make.

'''Ultron' was very complex. There was a lot of back-and-forth. My instinct is no. Just as an artist, I'm super f***ing lazy and that sounds like it would be hard. I don't think there's interest in it, right now.''