There's something I have been thinking of recently and I wonder if you could please help me find the right answer. Over the past years, I've noticed that characters in many English/American movies (or literature) are called Mr./Mrs., which is followed by the first letter of their name, often in a humorous way, for example in the movie 1776::
T. Jefferson: "But I burn, Mr. A!"
J. Adams: "So do I, Mr. J!"
Also, I noticed it also appears when a one character harbours romantical feelings for another one, such as Ms. Lovett who would sometimes call Todd Sweeney "Mr.T".
Such form of address is certainly not popular in my native language (Czech) and even seems slightly weird to me, yet I really find it interesting, so can anybody please tell me a bit more about it? Are there more situations when you use it? Does it have a history? Does its origin come from some particular book or something else? Thanks!