The Scottish actor portrays a younger version of Sir Patrick Stewart in the forthcoming prequel, but confesses he had to remind himself why he worked in cinema while on the set.
He said: "It's like any big ridiculous super-budget movie. Anything that size can make you feel like you're going mad, so you have to try to remember that when you watch those films in the cinema, it's an escapist experience."
However, he has revealed he is keen to work on sequels to the origin story, providing they can come up with a convincing reason why he loses his hair - as Patrick is bald in the later movies.
He said: "We haven't quite figured that one out yet.
"Maybe he gets really f**king psychotic and goes on a 'Taxi Driver' rampage. But there's so much interesting s**t that has to go down to make him who he becomes. Something f**king incredible has to happen!
"He can't just go to the hairdresser and they put on a dodgy rinse."