The actors - who play Thor and Captain America in the Marvel’s film, said the experienced 47-year-old spearheaded the mainly younger ensemble cast who include Scarlett Johansson, Mark Ruffalo, and Jeremy Renner.
Speaking on ‘Good Morning America’, Evans revealed: "I kind of give a lot of credit to Downey.
He's kind of the father of this group. If he hadn't done so well with those ‘Iron Man’ movies, I don't think this movie would have happened."
The 30-year-old thespian continued: "He came to the set with such a positive attitude and has such a great demeanor. We all kind of fell in line as a result of his disposition. He's just an amazing guy and he made it a really family atmosphere right away."
Hemsworth admitted that the rest of the cast were satisfied with their smaller roles compared to Downey’s in the motion picture.
The 28-year-old star said: "I think we all preferred it to be honest. When you do your individual films the responsibility rests on your shoulders whereas, this, you get to share the workload. And I'm happy to do that any day. It makes it much easier."