I was just thinking about this thread this morning, and now here it is, recently refreshed!

I thought I would note that Doris Day recorded one of these songs, like "You're Just in Love", where two parts are sung separately, then together (I assume it was done with the magic of multi-tracking.) I believe it was called "Everybody Loves a Lover". The verse that goes "Everybody ... loves a lover ... I'm a lover ... [etc.]" harmonizes with the verse that goes "Who's the most popular person ... ality? ... I can't help thinking it's no one ... else but me [etc.]", possibly with the pauses in different places for the two verses.

Don