The story about the nickname Jo Seung-woo gave Nam Joo-hyuk to tease him is funny.

Jo Seung-woo revealed Nam Joo-hyuk's taste in old songs.
They say that while filming, Jo Seung-woo teased Nam Joo-hyuk, saying, "You weren't born in '94, right? You weren't born in '97 either, you were born in '87."
I heard that someone witnessed Nam Joo-hyuk singing to Jay in the military, looking very satisfied.

They say he was born in '94, but he got that nickname because he sings old-school songs so naturally and well.