Name of song/source music piece - PLEASE???

Twice in the movie, Joan Crawford dances to the same slow, romantic piece of source music.

Daniele Amfitheatrof's monothematic, narrative score takes up the tune and uses it throughout the whole picture within many different variations. It appears for the first time in the main title after a few introducing bars. At the end, when the reporters suggest Ethel might soon try again to get out of her impoverished life, we hear the tune again.
It seems to represent Ethel's longing for a better, glamourous life.

I doubt Daniele Amfitheatrof wrote the piece himself. I'd like to know: What is the name of that piece and who wrote/performed it? Was it a well known piece of music in that period?

Thanks a lot!