Originally Posted by
Fornebufox
It's from a 1927 musical called Funny Face, written for Fred and Adele Astaire--had to look it up, I'm not THAT old. It's still a cabaret standard. You can hear a short clip on the jukebox at
http://www.gershwin.com/
Same name, different tune. The one stuck in my brain right now is the 1975 tune, which has different lyrics and melody.