Sung Si-kyung (; born April 17, 1979) 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, , Battle Trip, The Voice of Korea 2020, On & Off.
Sung was born and raised in Gangnam-gu, Seoul, South Korea. He attended Korea University. Sung's comeback track "ë ì¢ÂìÂÂ" (Even Now) released on his 7th album debuted at number 5 on Billboard's Korea K-Pop Hot 100 for the week of September 22. In 2019, Sung announced his first U.S. concert tour, a six-show trek across most major U.S. markets. Sung released an English song "And We Go" in May 2020.