Inside the issue - which is available for just £1.99 on your iPad - Johansson reveals that she was initially sceptical about Marvel's grand plan after making Iron Man 2.
"The idea of it is ridiculous!" she says. "When they told me that was the next step, I said, 'Oh, no! That is a disaster! You saw Thor, you saw Captain America, you saw Iron Man, those things don't go together!'"
Since starring in the third highest-grossing film of all time (Avengers, ahead of this year's Captain America: The Winter Soldier), she's come around.
Revealing that she's expecting the script for Avengers: Age Of Ultron "any day now", she promises "when it comes you can guarantee it'll be read in 25 minutes".
Captain America: The Winter Soldier opens on 28 March 2014.
The Avengers: Age Of Ultron opens in the US on 1 May 2015 with a UK release date yet to be announced.
For more from Johansson, pick up the brand new issue of Total Film, which is out now, and includes an exclusive look at the heroes of 2014, including The Amazing Spider-Man 2, 300: Rise Of An Empire, Muppets Most Wanted, Transformers: Age Of Extinction, and many more exciting new movies.
Looking forward to Captain America: The Winter Soldier? Tell us below...