Kang Sora as Shin Hae-sung
JB as Jang Woo-jae/JB (I:dn Member)
Jinwoon as Jin Yoo-jin
Jiyeon as Rian/Lee Ji-kyung (HershE Member)
Hyolyn as Nana/Kim Jae-hee (HershE Member)
Park Seo-joon as Siwoo (I:dn Member)
Ailee as Ailee (HershE Member)
Kirin students
Jr. as Jung Ui-bong (Lee seul husband in ep16, ep14-16 her boyfriend)
Yoo So-young as Park Soon-dong
Kim Jisoo as Park Hong-joo
Kirin teachers
Park Jin-young as Yang Jin-man (English Teacher)
Kwon Hae-hyo as Joo Jung-wan (Principal)
Kim Jung-tae as Lee Kang-chul (President)
Choi Yeo-jin as Ahn Tae-yeon (Vocal Teacher)
Park Kahi as Hyun Ji-soo (Dance Teacher)
Extended cast
Jung Yeon-joo as Lee Seul
Yoon Hee-suk as Shin Jae-in
Hwang Mi-sun as Rian’s mother
Jung Kyu-soo as Hae-sung’s father
No Jung-ui as Shin Hee-bong (Hae-sung’s sister)
Cameos
Kim Soo-hyun as Song Sam-dong (ep 1)
IU as Kim Pil-sook (ep 1)
Toxic as band performing with Yoo-jin in Hongdae (ep 1)
MYNAME as OZ Entertainment idol group (ep 2)
