DIA Jung Chae-yeon, who attended the rehearsal of Mnet 'M Countdown' held at CJ E & M Center in Sangam-dong, Seoul on the afternoon of the 25th, is posing.
About Jung Chae-yeon
Jung Chae-yeon, known mononymously as Chaeyeon, is a South Korean singer and actress signed under MBK Entertainment. She is best known for being a member of the South Korean girl group DIA, and for finishing 7th in the survival show Produce 101, making her a member of I.O.I.
 Wikipedia