Quote from : Star Wars: Episode V - The Empire Strikes Back Movie

C-3PO: That sounds like an R2 unit in there! I wonder if... Hello? How interesting.
Stormtrooper: Who are you?
C-3PO: Oh, my! I... I'm terribly sorry. I didn't mean to intrude. No, please don't get up.
[the Stormtrooper shoots C-3PO]