The event was attended by Shin Min-ah, Kang Daniel, Black Pink Index, Choi Siwon, Cha Eun-woo, Jang Gi-yong, Sung Hoon, Kim Myung-soo (Infinite El), and Gu Ja-sung.
About Choi Siwon
Choi Si-won, known mononymously as Siwon, is a South Korean singer, songwriter, model, and actor known for his work as a member of South Korean boy group Super Junior.
 Wikipedia