(this is the translation of the part where he mentions Taehyung)
"Taehyung is someone without any acting experience. He has filmed nothing other than music videos. He was the last actor I chose because he's the youngest Hwarang and I was looking for a cute and bright face. While looking for someone with such characteristics, I got to learn about BTS because my daughter is a fan of them. He was really handsome. So I contacted him and I positively considered about him when Taehyung said he had thoughts about acting. On the meeting day, he had good gaze and he was a person with many talents. Although he might lack in acting techniques, he seemed to have a great sense. We did a short reading and he wasn't perfect but he had great sensitivity of emotions. He felt like a person with great sense. I thought I should train him more so I delayed the filming. I gave him plenty of time to prepare and Seojoon really cared Taehyung. He guided him a lot and he helped him to practice his acting. He became better when Seojoon coached him. I think he really played his character well. There's an important episode in the second half of the drama after he builds up his character. I think you could look forward to Taehyung's acting in those episodes. His acting was good and it's something I can boast about. Kim Taehyung will receive great applause for Episode 17 and 18. He did very well. He was very lovable."
Original article here