You wouldn't know me from Adam

Has nobody heard the phrase "you don't know me from Adam"? I thought it was somewhere in the typical vernacular though it appears not. For those of you who have no fucking clue what I'm talking about the phrase basically means you don't know who I am. As in, you wouldn't be able to tell me apart from the first man on earth, even though you've repeatedly told you wouldn't sleep with me if I were the last man on earth.