Its a pretty old jazz standard by Nat King: https://en.wikipedia.org/wiki/Nature_Boy https://en.wikipedia.org/wiki/Nature_Boy There are tons of versions and va

Its a pretty old jazz standard by Nat King: https://en.wikipedia.org/wiki/Nature_Boy https://en.wikipedia.org/wiki/Nature_Boy There are tons of versions and variations of it It does in fact show up in Moulin Rouge: https://www.youtube.com/watch?v=ekCvBztYs_A https://www.youtube.com/watch?v=ekCvBztYs_A