Chorus line

[al.1]

I don’t remember the context, but have seen such an expression.
Is “chorus line” an idiom? The article I read had nothing to do with
singing.

[Gość: Steve]

I have heard it used to refer to the lower tier of actors who say a couple of words (and are not therefore extras), but who are quite irrelevant to the plot. It would naturally translate to non-entities elsewhere, being equivalent to "a load of yes-men". I don't know if that makes it an idiom.