"Regret" was sung by Li Daimo who is a Chinese singer. He rose to prominence after his runner-up of The Voice of China (season 1) with You Exist In My Song.
Regret was created by Peter Wong who once worked as a producer for Chyi Chin, aka, Nicholas Tse etc and built too many famous songs.
This song, Regret, was a little sad. With the deduction of Li Daimo, it described the bitter love. And why this song was released at Christmas Day? Li Daimo said, "He sincere hope this song can accompany everyone and make us not feel alone at Christmas".