Joss Whedon says he found Avengers: Age of Ultron so tough during filming that he thought he might 'die.'
Whedon is back in the director's chair for the highly anticipated sequel to Avengers Assemble, which sees the writer/filmmaker juggling eleven central characters this time around.
And he admits the he struggled to juggle all of these characters but enjoyed delving into those that do not currently have their own franchises.
Speaking to The Guardian, Whedon said: "It is tough. There's basically 11 main characters in this movie, which is quite frankly too much. I may die.
"Thor's probably the hardest to write at any point because his adventures tend towards the legendary and you can only have so much of that before people start to go: 'Wait a minute, whaaaat?'
"But the fun of the thing is taking Hawkeye and the people who don't have their own franchises - Banner, Natasha, the new guys - and delving into their lives."
Age of Ultron sees Whedon reunite with Robert Downey Jr, Chris Evans, Scarlett Johansson, Chris Hemsworth, Mark Ruffalo, Jeremy Renner & Samuel L Jackson, while James Spader, Paul Bettany, Elizabeth Olsen, and Aaron Taylor Johnson are the big new additions to an exciting cast list.
And while Avengers may be set to be one of the biggest movies of 2015, Whedon reveals that he didn't focus on what the fans wanted to see in the movie - instead indulging the fanboy in himself.
He continued: "I don't really think about the fans. I think about what I want because I'm the guy who's taking the comic book he read as a kid and turning it into a movie that I want to see as much as I want people to see it.
"Kevin Feige and I are fanboys, straight up. But we also know that if you just spend your time catering to the fans you make something that is hermetically sealed. The first question we always ask is: 'What is the way in for someone who has never seen a superhero movie?' You need to be thinking about everybody all the time."
Avengers: Age of Ultron is being tipped to take $200 million in its opening weekend in the U.S. and on course to rival Fast & Furious 7 for the crown of highest grossing movies of 2015 so far.