Kim Jong Kook and Lee Kwang Soo show off their friendship on 'The Sound of Heart' > TV-MOVIES

Photo: 'The Sound of Heart' screenshot

Actor Kim Jong Kook made special appearance on web drama 'The Sound of Heart.' He played the role of twin brothers named 'Jong Wook' and 'Jong Kook.' 

Kwang Soo and Jong Kook met each other while fimling SBS variety show 'Running Man.' Jong Kook chased Kwang Soo in the show. Meanwhile, Lee Kwang Soo is currently starring in 'The Sound of Heart' as the male lead, Jo Suk. ​

Korea.com's Emily You contributed to this report from Seoul. [E-mail: maintyoung@korea.com]