Sung Si-kyung is a South Korean singer, entertainer and television host. He debuted in 2001 and has released eight studio albums in Korean and two studio albums in Japanese. He has also hosted and appeared on numerous South Korean variety television shows including 2 Days & 1 Night, Witch Hunt, Non-Summit, Duet Song Festival, Vocal War: God's Voice, Battle Trip, The Voice Of Korea 2020, On & Off.

2 Days & 1 Night is a South Korean reality-variety show that airs every Sunday at 6:25pm KST on KBS2 beginning August 5, 2007. 1 Night 2 Days used to be one of the two segments on Happy Sunday. The episodes are also uploaded with English subtitles weekly on YouTube through KBS World's official channel. The show's current cast members are Kim Jong-min, Yeon Jung-hoon, Moon Se-yoon, DinDin, Na In-woo, and Yoo Seon-ho. The show's motto is "Real Wild Road Variety." Its main concept is to recommend various places of interest that viewers can visit in South Korea. Filming for every new trip is usually done 2 weeks prior to broadcast on KBS2.