First usage of "they're standing right behind me, aren't they?"

[Flywheel]

TV Tropes’ Right Behind Me page has examples going back to the Victorian novel North and South, but their earliest example of the line “he’s standing right behind me, isn’t he?” seems to be City Slickers.

Didn’t you guys see? The man was hanging the hired help! And, did you notice his eyes? He has crazy eyes. He’s a lunatic! We are going into the wilderness being led by a lunatic! He’s behind me, isn’t he?