What do people say that a performer is "on" a TV show but "in" a movie? (e.g. "Before she was in the movie Serenity, Jewel Staite was on the TV shows Firefly and Space Cases.")
Seriously. I've wondered this and never figured out a reason. Anyone? Anyone? Bueller? Bueller?
(Reposted from this two-year-old post...Yes, I'm still wondering...)