Smack me on the a** and call me judy

Origin of the phrase: smack me on the a** and call me judy

I don't know the origin of the phrase, but I think I know the origin of its current popularity. A lot of people have watched the TV series, "Friends." And a lot of people have asked what the line means.

Friends Episode 1.15
Steve: Well, smack my a** and call me Judy! These are fantastic! Monica: Oh, gosh, I'm so glad you liked them! Steve: Like 'em? ...
www.friends-tv.org/ zz115.html

I suppose it might equate to "Well, I'll be gosh-durned," or perhaps, "Well I'll be a sonofabitch," in some other context. It comes from somewhere, for sure, but I've no idea where. It seems preposterous to think of what Punch might do to Judy, but nothing else comes to mind. SS