Yoo Sung Eun and rapper Kisum made a wave on the May 27 installment of 'Immortal Song'.
SEE ALSO: BTS return to Korea and to hold a press conference after their success at the 'Billboard Music Awards'
On the 'Lyricist Special' of the show, Yoo Sung Eun and Kisum teamed up for a cover of Lee Soo Man's "Wave". Kisum revealed, "I've been friends with Yoo Sung Eun since my trainee days. We've released an album together before too. It's my first time on the show, and I'm not nervous because I'm appearing with a friend."