Chris Hemsworth had to under eat for 'Rush'.

The 30-year-old actor - who plays James Hunt in the biographical action film - had a short amount of time to drop the pounds in order to fit into the Formula One race car, so he under ate and worked out to the point of exhaustion, which he admits affected the people around him.

Speaking to Collider, he said: ''It was kind of everything in reverse - over trying and over eating and that to burn the muscle. I had such a limited period to do it in and it was a pretty moody experience for everyone around me at the time.''

The hunky star admits he feels like he's won the actor's lottery to be able to play such a big role in the 'Thor' franchise and then to be able to slot in other movies in between.

He explained: ''I pinch myself, it's crazy. To be able to be a part of something like 'Thor' and the 'Avengers' and it be so wifely successful and then to be able to it in films like this ['Rush'] in between is the dream and to be able to have the freedom and the choice to be able to mix it up. To be able to from something that is a big spectacle and go into more intimate. I absolutely feel like I've won the lottery.''