After gaining respect as an actor in Hollywood, Jon Favreau made the transition to the director’s chair look easy with such efforts as Elf and Zathura. He told Tara Bennett about helming Iron Man, which is shaping up to be one of this year’s must-see blockbusters.

Robert Downey Jr. praised working with you…

I think he is being kind. There is always collaboration between the filmmaker and the star. You have to put so much footage in the camera and try so many things to give the filmmaker the ability to make decisions in post-production.

When you are a supporting character, you come in and rip it up and they either use you or cut you out. If you get laughs, they keep you in. If not, you go away. When you are the lead, it’s a lot of back and forth. In one sense there was a lot of second unit performance done and we had to discuss how Iron Man would move and act and fight. All the stuff we are doing with ILM featuring him flying is choreography I worked out with a whole different group of people. But he had to come back in and voice it and then do close up work inside the helmet, so there is a lot of back and forth between us.

You were fairly open about the process of making Iron Man on your MySpace page. Were you worried about an internet backlash or spoiler leaking?

There are certain filmmakers like Spielberg who have been around long enough that you can keep a completely button-downed, closed set. People will give him the benefit of the doubt because of his body of work. But when you are dealing with a character like Iron Man and you are coming in without a body of work in the genre you have to make a case for yourself.

Plus, the fans are a tremendous resource for me to learn what people expect of this character. There is no way I can go through 40 years of comic books and learn everything I need to know about this guy. So in passing out information and hearing back from people…you learn what people like, who they gravitate to and what their concerns are.

Certain filmmakers like to give complete access to the set and do weblogs everyday, but for me that felt like it would be revealing too much. We have been very lucky that the reaction to the official and unofficial material has been very positive.

Did you ever fear how people would react to your approach to the genre?

I remember Mark Steven Johnson’s concerns and challenges that he faced [with Daredevil]. You had Fox that wanted a movie that was geared toward everybody so there were things they were able to do from the books and things they weren’t able to do.

[Johnson’s] a real fanboy who wants to stay as true as he can. I learned things…like how lucky I was to be working with Marvel as a studio. They were no longer the people lobbying to the studio for their vision - they were the people with the money. Kevin Feige knows more about Iron Man than I do and he was there not just as a boss, but as a consultant. He was an expert on the books and anytime I had a question I would get a binder full of pages from 40 years of books. Their concerns were different. It was fun to work on as a filmmaker.

Would you say the film’s more about Tony Stark or Iron Man?

Iron Man is different from the DC heroes where Batman is the character and Bruce Wayne is his cover story or Superman is the character and Clark Kent is the disguise. Tony Stark is the character and Iron Man is his alter ego that he only starts to explore later.

You make an appearance in this film as Hogan…

Yes, all the rumors were online [about my role] and it’s amazing what a snowball it turned into. I don’t want to tell too much but I am wearing a wig and it was an impetus to start losing weight knowing that I would be onscreen! I was very happy to be in the film.

How did you settle on the film’s villain, Obadiah Stane/Iron Monger?

It’s very hard to choose a villain for Iron Man because the big villain is The Mandarin. But The Mandarin is not the type of villain that you can feature right off the bat. You can’t stay true to the books without putting off a mainstream audience. And as The Mandarin is depicted in the books, I don’t know that that depiction would work nowadays – magical rings shooting? I don’t know if that is the thing people are expecting.

I look to Star Wars where you had the Emperor, but Darth Vader is the guy you want to see [Luke] fight; and then you work your way to the time the lightning bolts are shooting from [the Emperor’s] fingers and all that stuff. But you can’t have what happened in Empire Strikes Back happen in A New Hope. You can’t have Sauron be the first person that Frodo meets up with [in The Lord of the Rings]. You have to lay enough down in the storyline so, as the story unfolds, you get there.

Our depiction of the universe and the reality that we are dealing with is that there aren’t other superpowers in this world. I wanted everything to come out of the technology that Tony Stark developed and watch it grow out from there. As you cut the movie together and see how it plays, you can then go deeper and deeper.

Iron Man opens in US and UK cinemas on 2 May 2008.