a case of mistaken identity
An instance in which one is thought or assumed to be someone else. Officer, this is a case of mistaken identity—I can assure you that I did not rob anyone! I'm sorry, ma'am, it seems this is a case of mistaken identity. We're looking for a different person who's a redhead and about your height. I have an identical twin, so my daily life is basically a case of mistaken identity.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.