If you don't get the "Old Sport" reference, you haven't read the book, or seen the movie. Jay Gatsby loves to use this expression, which he thinks makes him sound like an English Gentleman.
If you call someone "Old Sport" these days you are being ironic, mocking even. Daisy's husband, Tom Buchanan, got really irritated by the phrase "Old Sport" in the Great Gatsby novel. He thought Gatsby was being pretentious. ( He was right)
I could, and can, ramble on at length about The Great Gatsby, which is a book that I love. I haven't yet seen the new movie. The reviews seem to be mixed, but the clothes and jewelry look fabulous. Great Gatsby fashion is everywhere right now. Even before the Gatsby movie, Downton Abbey Season 3 had focused on the post war 1920s era. I'd love to look like the elegant Lady Mary Crawley in Downton Abbey.
My nod to the Great Gatsby fashion trend is to wear vintage style Gatsby era earrings. I love earrings. Wearing earrings makes me happy. I like quite big earrings- nothing too subtle. I'm on the look out for fabulous Great Gatsby style earrings, and I'll share the best with you.