The two stars, who worked together for film 'Hyung', continued their bromantic chemistry into the recording studio.
"Don't Worry" is the second collaboration project by music director Kim Tae Sung. The track is originally by Jeon In Gwon, and also well known as 'Reply 1988' OST sung by Lee Juk.
Listen to D.O. and Jo Jung Suk's bromantic version of "Don't Worry" above.