We first see the phrase in a British ballad dating from 1870 that includes the line "Whatever I tell you is on the QT". The writer's name is lost to time. By the end of the century it had appeared in other songs including the memorable "Ta-ra-ra-boom-de-ay", sung to great acclaim by one Lottie Collins, whose knickers did not 'fly away' nor did they go 'on holiday' in the original version of the tune.
(Interestingly, that tune has stayed popular in the East End and is now used by West Ham fans to serenade and celebrate Paulo Di Canio).
You mentioned an appearance in US literature
It's certainly more common in US English these days. One of the most celebrated uses of the phrase comes in the 1990 James Ellroy noir novel L.A. Confidential (also an Oscar-winning Hollywood thriller starring Kevin Spacey, Russell Crowe and Kim Basinger). Ellroy loves words with a punch, his work replete with such as 'zorched' and 'schtup' and 'bonaroo'.
|Danny DeVito plays Sid Hudgeons|
Talking of Hollywood - On The QT sounds like the name of a film
It is, but the title was better than the finished product. Its a blink-and-you-miss-it coming-of-age drama, made in 1999, about a violinist from rural Michigan who discovers the Meaning Of Life And Stuff while busking in the New York subway. James Earl Jones starred in one of his more hush-hush leading roles.
Other artistic appearances
With a play on words that even the teenyboppiest of fans could appreciate, Jason "QT" McKnight was indeed the 'cutie' member of a spoof boy band called 2gether. They were an MTV phenomenon before anyone thought of filming Ozzy Osbourne's fireside homilies, but sadly the actor playing QT died.
Why did the phrase survive and prosper
Time to get serious. In his classic study of words 'The American Language' (1921), HL Mencken records the fascination Stateside with abbreviations - OK, PDQ, COD, as well as on the QT. Mencken suggests they were important in helping non-English speakers make themselves understood in the linguistic hothouse that was immigrant New York. If you can say lots in a few short, sharp letters or sounds, you can get by. Which is why swearing is so popular!