The feud between Nestlé, which makes KitKat, and Mondelēz International, the makers of Kvikk Lunsj, began in 2010, when Nestlé first attempted to trademark the shape of its four-finger KitKat chocolate bar in the UK.
Mondelēz disputed the application, arguing that Kvikk Lunsj, which was created in 1937, also had a four finger appearance, and could be found in some UK shops.
Norwegians consume an average of nine Kvikk Lunsj bars a year, three of which are consumed at Easter, when Norwegian families traditionally go off on cross-country skiing trips, fuelled by Kvikk Lunsj calories.
Rowntree's began making a four-finger bar in 1935, but called it "Rowntree's Chocolate Crisp", only renaming it "KitKat Chocolate Crisp" in 1937.
On Wednesday, the European Court of Justice ruled that the appearance of KitKat's chocolate covered wafers was not distinct enough to trademark.
In a few months time the case will return to the UK's High Court, whose judges will decide if Kvikk Lunsj will remain on sale in the UK.
"It is up to the British courts to decide, on the basis of this response, if the form of KitKat chocolate bars can be registered as a trademark or not," the EU court said in a statement.
For now, Kvikk Lunsj loving Brits can breath a sigh of relief, if they can find the product in a UK shop that is.