KBS 2TV Happy Together Season 4' recording was held at KBS annex in Yeouido-dong, Yeongdeungpo-gu, Seoul on the afternoon of December 22.
Na-eun was present on the day.
MC Yoo Jae-seok, Jeon Hyun-moo, Cho Yoon-hee, and Jo Se-ho guest at the end of the year were Moon Hee-joon, Tony Ahn, Hwangbo, SAM KIM, Paul Kim, April Na-eun and Naha Eun.
About Moon Hee-joon
Moon Hee-joon is a South Korean pop rock singer-songwriter signed under SidusHQ. He initially rose to fame as the leader of former boy band H.O.T. under SM Entertainment.
 Wikipedia