Please excuse my vanity.
Aren’t we all?
Read any article on ancestry breakdown and you’ll see why that is. So yes, you are related or descend from royalty, and so do many celebrities.
I’ll give you a very simple explanation.
Look at the structure of a family tree.
You’re at the bottom. Above you, there are your two parents. Then, above them, there are their four parents, which are your grandparents. Beyond that, you have eight great-grandparents, sixteen great-great grandparents, and so on.
You don’t even need to go too far, because even 10 generations back, you’ll have 1024 ancestors on your family tree. Some simple maths, and if you go 20 generations back, you then have over a million ancestors. With 30 generations back, you have over a billion ancestors… Which actually sums up to more people than were actually alive on Earth 30 generations ago.
So, simply put, if you go back enough generations (in any given geographical area) then you can safely say that people in the same area today have ancestors from back then. All people.