Buck's Fizz VS Mimosa

Today, out of pure chance, I finally learned the difference between two cocktails that seem exactly similar: the Buck's Fizz, a British classic I discovered here in England, and the Mimosa, which I knew from before, but never quite got into. Both are made of champagne and orange juice. The only difference is the quantity: the Mimosa has half parts of each beverage, while the Busk's Fizz is two parts champagne and one part orange juice. No wonder I always preferred Buck's Fizz. Mystery solved.