Twenty Years Old: Reparto
Lee Yu-ri
Chae-ri
Gong Yoo
Joon
Shoo
Soo-young
Jung Sung-yoon
Tae-hyun
Moon Ji-yoon
Sang-hyuk
Lim Seong-eon
Min-hee
Jo Dal-hwan
Seok-goo
Kim Yong-geon
Sang-hyuk's Father
Lee Mi-young
Sang-hyuk's Mother
Kim Ji-woo
Song-yi
Yoo Seo-jin
Professor