On the KBS2 variety show 'Problem Child in the Rooftop Room,' it is revealed that actress Kim Sook was the partner in Yeon Jung-hoon's first kiss scene.

Yeon Jung-hoon appears as a guest on episode 322 of 'Problem Child in the Rooftop Room,' airing on the 24th. As Song Eun-i, Kim Sook, Kim Jong-kook, Hong Jin-kyung, Yang Se-chan, and Joo Woo-jae engage in talk and quiz together, Kim Sook reveals her past connection with Yeon Jung-hoon, stating that she was his first kiss scene partner.

Kim Sook showed confidence, saying, "Before Han Ga-in, there was Kim Sook," and Yeon Jung-hoon acknowledged this as well. The two shared the experience of filming their first kiss scene together in a sitcom that Yeon Jung-hoon appeared in during his rookie days.

Behind-the-scenes details from the shoot were also revealed. Yeon Jung-hoon recalled, "Sook noona said, 'I have no emotions and no time right now, so just stay still. I'm going in for the kill in one take.'" Kim Sook added, "I was so busy at the time that I was living minute by minute," drawing laughter.

That day, Kim Sook described herself as the "original thief," and Kim Jong-kook consoled Yeon Jung-hoon by saying, "You got the bad luck out of the way early, so things could only get better."

In relation to this, Yeon Jung-hoon mentioned that his wife Han Ga-in's first kiss scene partner was senior Yoo Jae-suk, surprising everyone on set. Yang Se-chan added to the laughter by saying, "Your family really drew the short straw."

Meanwhile, 'Problem Child in the Rooftop Room' airs every Friday at 10:10 PM.