Nam Tae Hyun, who produced the new song, revealed, "'Who's This Song For?' was originally a warm love song. But I had to let a loved one go while working on the track. Seeing myself lost after losing my reason to live, I rewrote the lyrics to depict the sorrowful trace of love left behind."
"Who's This Song For?" is set to release at 6 pm KST on December 6.