Father is Strange (2017)

Mi Yeong, Hye Yeong, Ra Yeong, and Joon Yeong are the kids of Yeong Sil and Han Soo. They seem like the average Seoul family, with the typical Seoul problems, but that all changes when Jung Hui, an actor, and former K-Pop idol, ends up in their doorstep claiming that Han Soo is his biological father. The family goes through thick and thin, one marriage after the other, trying to figure out why their father happens to be strange.