The way he talked out of the side of his mouth, his facial expressions, his mannerism's, his attitude...even his voice! I'll admit it was the first time I had been really impressed with casting.
He had a dialect coach.
Also, he's been a trekkie since he was 7 years old, and is, I'm told, the only actor in the entire cast who actively sought out the part. he played.
Bookmarks