Kim Hye Yoon says working with SF9's Rowoon gave her neck pain.

On the January 4th episode of 'Knowing Brothers', Kim Hye Yoon revealed filming 'Extraordinary You' alongside Rowoon caused her a bit of pain. She explained, "I'm 160cm (~5'3"), and Rowoon is 190cm (~6'3"). Viewers said it was a heart-fluttering height difference, but it was really tough during filming."

Kim Hye Yoon continued, "After filming, I had a dull pain at the back of my neck. It's because I kept having to look up." Rowoon added, "I had a rule that I would only wear low shoes. I couldn't wear dress shoes. When Lee Jae Wook and I talked, Hye Yoon would say she couldn't hear what we were saying." 

Did you notice Kim Hye Yoon and Rowoon's height difference?