Alfred Hitchcock was way ahead of his time.
In this rare sound test recording for Hitchcock's 1929 film "Blackmail" he makes the first ever known recording of the joke "that's what she said." Well, his joke is actually the "as the girl said" version, but the joke has evolved, like all the great ones do.
So, Michael Scott, meet Alfred Hitchcock, who did it before you. That's what she said.