The Biebs doesn't mind being approached by fans - but he does have some strict rules in place about how to do it.
The singer told Teen Vogue back in 2010: Just talk to me. Ask me how I'm doing. Introduce yourself instead of yelling, 'Justin! Justin! Justin! Can I have a picture?'
"And don't come up to me while I'm eating. How would you like it if I came into your house and started taking pictures of you while you were eating? I hate that."
Have you all got that? Good.