I was curious, though, when I started to see chatter online about Aldi’s Diet Cola being a dupe for the king of all Diet Cokes: a McDonald’s Diet Coke. Is Aldi’s diet cola a dupe for a McDonald’s Diet Coke? In this case, the packaging for Aldi Diet Cola is freakishly akin to that of a Diet Coke: It’s a light silver can with red lettering. I am convinced that if you poured the Aldi Diet Cola into a McDonald’s cup, I wouldn’t know the difference. It really is a super dupe for McDonald’s Diet Coke!