Kahi, formerly of After School, showed off her close friendship with actor Ahn Jae Wook in a backstage photo.

"I came back from seeing 'Crown Prince Rudolph'~," she posted to her Twitter. "Jae Wook oppa, you worked so hard~ thank you for the wonderful performance!!!!"

'Crown Prince Rudolph' is a musical stage play featuring the actor from MBC's hit drama, 'Light and Shadow'.