 The US Treasury Department lists Kim Jong-un's official birthdate as 8 January 1984.Kim Jong-un is the second of three children Ko Yong-hui bore to Kim Jong-il; his elder brother Kim Jong-chul was born in 1981, while his younger sister, Kim Yo-jong, is believed to have been born in 1987.He is the grandson of Kim Il-sung, who was the founder and led North Korea from its establishment in 1948 until his death in 1994.