TIL Kit Kat is produced globally by NESTLE, except in the US where it's made by their competitor HERSHEY

Use of the name Kit Kat or Kit Cat for a type of food goes back to the 18th century, when mutton pies known as a Kit-Kat were served at meetings of the political Kit-Cat Club in London.

The origins of what is now known as the Kit Kat brand go back to 1911, when Rowntree's, a confectionery company based in York in the United Kingdom, trademarked the terms Kit Cat and Kit Kat. Although the terms were not immediately used, the first conception of the Kit Kat appeared in the 1920s, when Rowntree launched a brand of boxed chocolates entitled Kit Cat. This continued into the 1930s, when Rowntree's shifted focus and production onto its Black Magic and Dairy Box brands. With the promotion of alternative products the Kit Cat brand decreased and was eventually discontinued. The original four-finger bar was developed after a worker at Rowntree's York Factory put a suggestion in a recommendation box for a snack that "a man could take to work in his pack". The bar launched on 29 August 1935, under the title of Rowntree's Chocolate Crisp (priced at 2d), and was sold in London and throughout Southern England.

The product's official title of Rowntree's Chocolate Crisp was renamed Kit Kat Chocolate Crisp in 1937, the same year that Kit Kat began to incorporate "Break" into its recognisable advertising strategy. The colour scheme and first flavour variation to the brand came in 1942, owing to World War II, when food shortages prompted an alteration in the recipe. The flavour of Kit Kat was changed to dark chocolate; the packaging abandoned its Chocolate Crisp title, and was adorned in blue. After the war the title was altered to Kit Kat and resumed its original milk recipe and red packaging.