On the May 19th installment of 'Knowing Brothers', Hwa Sa, Hwang Bo, Hyoyeon, and Dayoung featured as guests. Hyoyeon mentioned, "I'm curious about something, Hwa Sa. I filmed a show with Whee In a few days ago, and I heard you two were classmates in junior high school. Isn't it uncomfortable because the closer you are, sometimes you fight more?"
Hwa Sa revealed, "We fight when we need to fight. I think it's healthier than not talking about it. Actually, Whee In and I got into a fist fight once. We were drunk, and we totally went at each other."