Dance Magic Dance

I know you're not going to believe this, but there were movies made before "Labyrinth". The art of filmmaking existed, though it was of course flawed and struggling until the celluloid perfection that is "Labyrinth" was created. Behold! Some of it's puppet-stringed glory!:
So imagine my shock and disbelief when someone told me the other day that the wonderfully recognizable nonsense exchange between David Bowie and muppet was lifted from a Cary Grant movie!! Behold a second time!:

The Quote starts quickly and ends 20 seconds in. But don't let that stop you from enjoying the song and dance afterwards. And now, the clip from the Cary Grant movie:

The quote doesn't start until 1:53 in that one, and I suggest you fast-forward to it unless you like your movies black-and-white and your "Gee Whiz!"s earnest.

Isn't that crazy? Nearly the exact same dialogue. What other secrets lay hidden within the Labyrinth? Besides a way to the Goblin Castle, I mean.