If I know them well, then I would totally talk to them about KPOP! If I didn't or got easily embarrassed in the place I'm at, I probably not bring it up. I would probably act like I didn't care that much with like a smile and a nod.
I've done that before. I've only talked with KPOP to few other people. But I remember a group of people in my class revealing that they were big blinks!
But with Jae-6 here... 
