You might not have ever heard of “Maurice Micklewhite,” “Olivia Jane Cockburn” or “Diane Hall” — but you’ve certainly heard of the actors who were born with these names. When the Hollywood system started, people commonly took simplified versions of their names to make them easier for people to say. Doris Day is much simpler than “Doris Mary Ann Kappelhoff” and Clayton Holmes Grissom picked “Clay Aiken” when signing up for American Idol — because it was just more memorable. Or if you’re Albert Brooks, there’s no fucking possible way you can use your real name — because…well, you’ll see.

Here are 55 people whose real names might surprise you.

1. Katy Perry

Real Name: Katy Hudson

The singer changed her name to avoid confusion with that other Hudson she shares a name with: Kate Hudson.