SS501’s Heo Young Saeng is joining the O.S.T. album of SBS drama “Protect the Boss.” His track titled, “Sad Song,” will be used as the love theme song for Ji Sung and Choi Kang Hee’s relationship. It is written and produced by Jeon Hae Sung, who’s known for his works in the O.S.T. albums of other hit dramas such as SBS “Secret Garden” and MBC “Greatest Love.” Following JYJ’s Jaejoong, Lyn, and A-Pink, Heo Young Saeng will become the fourth artist to be part of the drama’s O.S.T.

“I’m glad to be part of the OST of ‘Protect the Boss.’ I hope my song blends in well with this great show,” Heo Young Saeng said in an official statement.

“Sad Song” will first be revealed on August 24th during the seventh episode of “Protect the Boss,” and be released online on August 31st.