The actor told ShortList that director Ridley Scott has said his android David is "like the butler" on the ship where he serves.
"But there's a vanity to him," he added. "And he always has the answers so there's a swagger to him, too.
"In fact, I think he might be kind of creepy. I do creepy well."
The Shame actor then quipped: "If you're looking for weird or creepy in a robotic style, call me."
Fassbender continued on the character: "What I thought was interesting was him being programmed to react in a certain way. And part of that is him blending in with humans, so does an ego develop to facilitate that?
"He's there to serve them, but he's sort of disliked because they think he might be superior to them. Or just different. Because humans have that thing where they're like, 'Something's different? Persecute!'."
Photo gallery - Prometheus: