Who Are You and What Have You Done With His Body, origine of the phrase

[Arga]

Does anyone know in which movie this phrase has been used for the first time?

"Who are you, and what have you done with his body" (or something similar).

It is nowadays usually used in a fun way, when someone doesn't behave like they normally do; but I think this sentence had been used seriously in a movie before, maybe about an alien invasion.. i'm not sure about the reference.

If one of you have got an idea, that would be awesome.
Thanks

[DigiFluid]

I don't think it has to do with any sci-fi at all (seems too common a phrase for that), but if I had to guess at something popularizing it I'd say "Invasion of the Body Snatchers".