Remember how in my 2nd fact, I said that the voice of Snow White (Andriana Caselotti) was held in contract so she could not perfrom in any show or movie again? 

Well, I just found out, she was able sneak an uncredited voice in The Wizard of Oz. When the Tin Man was singing If Only I Had a Heart, Caselotti was the voice who said "Where for art thou, Romeo"