Robert Downey Jr has revealed that the Iron Man suit has become more comfortable in the latest film.
"The funny thing is Mark 1 was really clunky, but it was a ball. And if you ask some people, they still love the suit before it was a suit that anybody knew from the comics or from the franchise per se," he said.
"Then it's been just a bunch of guys and gals standing around figuring how to make it survivable and how to utilise the resources of other departments. So, for me it's gotten easier and easier.
"It's gotten to the point where I can be wearing a pretty significant amount of gear and not be uncomfortable at all for long periods of time. I have much less to complain about, which has left me a little bit confused, but has also helped me to refocus my efforts back again on story and on my co-stars," he added.
Robert - who will reprise the role for the Avengers sequel, Age Of Ultron - revealed he enjoys playing the character.
"What happened to the fun? That's the first thing I was thinking, and I always have to remind myself as I absolutely insist on having fun," he said.
"Why do I forget? Why do I become someone who is just in the slog of the pressure of the schedule? Tony Stark is a joy to play and charity starts at home," he added.
Iron Man 3 is out on DVD and Blu-ray now.