Kim Jong Il had another son with Ko Young-hee. Kim Jong-chul was reportedly born in 1981, the middle son of Kim Jong Il. Briefly it was believed that he would become the heir apparent to his father but it was soon revealed that he was far from his father's favorite son.
Kenji Fujimoto, who was Kim Jong-Il's personal sushi chef, wrote in a memoir that Kim Jong Il thought Jong-chul was "no good because he is like a little girl," and that he thought Kim Jong Il preferred his younger son with Ko Young-hee.
The eldest son of Kim Jong Il, Kim Jong Nam, was also at one point assumed to be the heir to North Korea. Born to the leader's first mistress, Song Hye-rim, in 1971. As the nation's top actress, Song was a married woman with a daughter when Kim Jong Il fell in love with her in 1968. For that reason, she was disapproved by the party, and sought exile in 1996. She reportedly died later in Moscow.
Kim Jong Nam's favorite son status fell apart in 2001 when the then 30-year-old tried to enter Japan with a fake Dominican Republic passport to visit Tokyo's Disneyland. He was arrested when he arrived at New Tokyo International Airport. The incident received widespread publicity and strained relations with his father.
According to The Chosun Ilbo, a South Korean newspaper, Kim Jong Nam, who is also known to be outspoken and enjoys gambling, has two wives, one of which lives in Beijing and the other in Macau, a mistress, and a number of children.