Choi Youngjoon is a dancer and choreographer. He was the dance trainer/mentor for trainees on Produce 48.
Choi Youngjoon is a renown choreographer in the Kpop community. He started to dance when he was younger by performing on music shows as a backup dancer and then working as a live DJ at night. Then Minwoo, a member of Shinhwa, brought him into work with Shinhwa and show his choreography skills through their music. This allowed him to gain recognition and work with a multitude of other artists and groups.
(Source: Kpop Fandom)
