Fassbender, 35, came up with the "Alien" director in the sci-fi movie and he says that he had a healthy amount of fear before he started, reported Contactmusic.
"You're very much aware of that and that it is Ridley and that it is this world and there is that pressure, but that's good. That gives you a healthy amount of fear and then like I said I try to get all of the preparation squared away and then on set really try to have fun," he said.
Fassbender also says the best thing was enjoying playing the character and having fun in the movie, which also stars Charlize Theron and Guy Pearce.
"I knew that I wanted to have fun with this character. I really wanted to enjoy it and Ridley and I seemed to click immediately in terms of what was going on with the character and the freedom to try things out with him and to find the humour in there."