Twinkle Twinkle, Little Star

On our plan ride home from Asheville Juliet just started singing this song.  I was dumbfounded.  First of all, she has yet to even sing a song in it's entirety and, secondly, I did NOT teach her this song.  Yes, we have sung it a time or two (or even ten) but it is not one of the songs we sing regularly.  But, alas, she knows every word...