The pre-rehearsals included Golden Child, Gugudan, The Man Black, Mighty Mouse, MonstaX (MONSTA X), BtoB (BtoB), Seo In-young, Stray Kids (StrayKids), IZ*ONE, ATIZ, April, MXM (MXM), Wikimiki (WEKIMEE) KI), JBJ95, Chae Yeon, Kwill, TWICE, Promis Nine, Hot Shot and Hay Girls attended.
BtoB (BtoB) member Yook Sungjae poses.
About BtoB
BtoB is a South Korean boy band formed in 2012 by Cube Entertainment. The group consists of Seo Eun-kwang, Lee Min-hyuk, Lee Chang-sub, Im Hyun-sik, Peniel Shin and Yook Sung-jae.
 Wikipedia