Park Charlotte as you

Charlotte was raised in a wealthy family as her parents raised her as they saw fit, Perhaps this is the reason why she is a pliant, obedient girl, who has difficulty expressing herself.

Jeon Jungkook as himself.
Jungkook is a talent seeking to become a star although his parents wants him to focus on his study to become a doctor.

Kim Taehyung or V as himself
Taehyung parents divorced, so taehyung became recorded under his mother's family officially register. His mother then remarried, but taehyung had a difficulty getting along with his stepfather and ultimately ran away from home.