Anyone who knows the band/artist performing the version Arthur plays on her gramophone? Best version I've ever heard of this Cole Porter song.
Argueing over the internet is like the special olympics, Even if you win. You're still retarded.
I googled a bit, but to no avail. It's probable that some of the dozens (hundreds?) of musicians employed by the studio arranged and performed it and thus didn't get any credit.
Tito Puente did a version that has a ?mambo? feel, but it's fairly different from the one in the movie, in part because it was done several years later + it's more improvisational:
https://www.youtube.com/watch?v=UYDopZUHFPs
Tommy Dorsey's version is nice:
https://www.youtube.com/watch?v=W4ehSanFvbI
And, of course, the incomparable Billy Holiday (to my mind, the ultimate version):
https://www.youtube.com/watch?v=fhu7x94kbzk
"All you need to start an asylum is an empty rom and the right kind of people."
I love how both Constance and Joe can't resist dancing to it -- he in the hallway, she in her room, both in various stages of deshabille, before they even know of one another's existence.
The camera cuts back and forth, creating the first "maybe these two should get together" moment in the film.