Regarding your 2nd question, I recall an NPR report on the DeBeer’s company establishing the first product placement marketing campaign through an ad agency called N.W. Ayer. They also employed Salvator Dali and Pablo Picasso during their extensive campaign that began the other slogan, “Diamonds are Forever.” I realize this doesn’t answer your question, but here’s a link to a site that has a whole lot of research on the diamond marketing “conspiracy” that has led men to pursue that carbon based rock solely because women have been taught to want them.
The book came first. Run out and get a copy, now, of Anita Loos’ brilliant Gentlemen Prefer Blondes (1925).
Then came the non-musical B’way show (1926), starring June Walker and Edna Hibbard as Lorelei and Dorothy; and a song of the same title, though not the one later written for the musical.
Next came the silent-movie version (1928), with Ruth Taylor and Alice White.
Then came the 1949 B’way musical starring Carol Channing, featuring the song you’re probably thinking of–the same song that was used in the 1953 movie version with Marilyn Monroe.
is easy. The song comes from the 1949 playGentlemen Prefer Blondes by Joseph Fields. The song was written by Jules Styne and Leo Robin.
is harder. The book Gentlemen Prefer Blondes, by Anita Loos, came out all the way back in 1925. I happened to have just finished reading in and so I’m pretty sure it doesn’t contain that phrase anywhere. But that gives 34 years for the phrase to have been uttered by someone.
My guess is that the phrase was original to the song, but we really, really need Eve on this one.