This is from the film of Antoine De Saint-Exupery's The Little Prince. The music was written by Frederick Loewe, the lyrics by Alan Jay Lerner. Rather dismissed in its day, it was also the subject of criticism by Lerner, who felt director Stanley Donen had interfered with the music to its detriment.
It has since attracted at least a small cult of fans, of which I am one, based on the strong performances of the actors and the very enjoyable (despite Lerner's criticism); memorable score.
The actors include Richard Kiley, who you'll see in this clip, Bob Fosse, in his definitive performance onscreen as a mature dancer and Gene Wilder, as a sensitive fox.
Steven Warner, who played the titular Prince, only made one other film, one I've never seen and I'm quite sure that no one remembers, only I do because it was featured in Dynamite magazine and I have that kind of memory. I remember being told I looked quite a bit like him when I was 8.
Oh, and I should mention that the only clip of this song I could find is from a dubbed version. But luckily, only the dialogue is dubbed, not Kiley's rich, Tony Award-winning (he created the lead in Man of La Mancha) singing voice. It's the song I really want you to hear anyhow.