Friend from Middle School

There was one time when we were at dinner, Oppa met someone from their middle school. Since I was not at the same middle school with them, obviously I don't know this guy. 

Guy : Hey Oppa, long time didn't see you? how have you been?

Oppa : I am good. How about you?

Guy : How long you been back from Jakarta?

Oppa : almost one year. You? did you just get back from Jakarta as well? 

Guy : No, I have been here for long time.

the conversation continue until this guy leave. And then......

Oppa : Hmmm... Who is that guy? 

Me : .......................................................