Paul Rudd didn't do ''anything fun for a year'' while he prepared to play Ant-Man.

The 46-year-old actor has revealed he spent 12 months getting into shape for his role as the Marvel superhero during which his strict diet and exercise regime left him feeling miserable.

He said: ''I didn't do anything fun for a year. I ate no carbs or sugar. I basically made health and fitness the focus of my day, for a long time.

''Like, we'd work out with a trainer and I worked with a guy who was doing tumbling and taught how to do flips and stuff like that. I was eating a lot of protein and vegetables. I was eating at very specific times of the day and I didn't drink any alcohol. I was miserable for about a year.''

However, the 'This Is 40' star credits all the hard work he put in in the gym for helping him get into the role and added he would have felt like an ''imposter'' if he hadn't been in peak physical condition to play the character.

Speaking during a press conference for 'Ant-Man' at London's Corinthia Hotel yesterday (07.07.15) he said: ''I knew I was going to be held accountable, so that made it a little easier. But I'd never done anything like that before to that extreme. Having the majority of my day built around that, instead of making fitness something I tried to build in as I went about my day was great.

''I woke up very early in the morning, I had lots of energy. It helped me to get into the mindset of this character. I figured if I'm in really good shape, I'd feel like less of an imposter in the role.''