The odds of finding one are lower than winning the lottery, but one woman managed the incredible feat.
Diane Olver, 74, cracked open an egg to find four separate yolks inside, beating odds of billions to one.
She was preparing a fruitcake for her son Nik and his partner Kim, both 39, when she took the egg from a Morrisons six-pack at around 2pm on Saturday.
Amazingly, she saw four small yolks fall out into a small cup.
Diane was absolutely flabbergasted at the half-inch yolks, commenting: Each of them was smaller than my thumbnail.
As you can imagine, she decided not to use the eggs for her cake, and kept them in the fridge instead so that she could show Nik and Kim.