Leonard Nimoy, who was not a scientist by any means but played...

Leonard Nimoy, who was not a scientist by any means but played one on TV, once ran into some real scientists from CalTech who talked to him as if he were a fellow researcher.
He didn’t know what they were talking about, so whenever they asked him what he thought about their work, he just nodded and said, “You’re on the right track.”
(Source)