On January 7th girl group SISTAR's vocalist Soyou released the OST Part 4 "Just Once" for MBC's hit drama "Empress Ki."

This song was produced by Lee Hyun Do and Soyou, and isn't your average ballad song. According to sources, "At times the song is reminiscent of a vast wind sound, at times it makes you think of the lonely moonlight in a faraway home, and at times it reminds you of a storm that comes at you. The strings blend with the poetic lyrics, is the beauty of the song." Some of the most talented people have contributed to the song, including Shin Hyun Kwon, Kang Su Ho, and Shim Sang Won, who have added to the depth and completeness of the song.

In particular, Soyou's pure voice is perfect in portraying the character Ki Hwang Woo's sorrow and longing. The song has been mixed and mastered by engineers to give the song a modern feel. The many talented hands that went into the song have been complimented left and right.

Soyou is currently starring on JTBC's "Great Marriage" as Jung Hoon Hee and Kim Tae Hwa's virtual daughter-in-law.