Ballad singer Sung Si Kyung surprised his fans by covering BTS’s “Boy With Luv” at his concert this weekend!

On December 21, Sung Si Kyung held the second night of his “The Song” encore concert at the Jamsil Indoor Stadium in Seoul.

Despite being famous for his slow, sentimental ballads, the singer gamely took on all seven BTS members’ parts in an energetic rendition of “Boy With Luv,” impressing fans by singing, rapping, and dancing his way through the hit song.

Check out two fan-taken clips of Sung Si Kyung’s one-man cover of “Boy With Luv” below!