Kim Jong-un: a profile of North Korea's next leader
Such is the secrecy of North Korea, the Hermit Kingdom, that until he was 20-years-old, no one even knew that Kim Jong-un existed.
The first mention of Kim Jong-il's third, and favourite, son, came in the memoirs of a Japanese sushi chef who claims he became a drinking companion of North Korea's "Dear Leader".
Kim Jong-un was born to his father's third wife, Ko Yong-Hi, who reportedly died of breast cancer in 2004.
The only photograph of the younger Kim, who is likely to succeed his father imminently, is a grainy black-and-white snapshot taken when he was 11-years-old.
In the picture, Kim Jong-un has the same snub nose and thin lips as his father, and the chef, Kenji Fujimoto, said he is indeed "a spitting image of his father in terms of face, body shape and personality". When North Korea's latest leader steps up to take the helm, we can expect him to be a "chip off the old block", according to Mr Fujimoto.
Reports in South Korea have described him as gung-ho and determined. There have been accounts of his fierce competitive streak when playing basketball with his middle brother, Kim Jong-chul, who was cruelly dismissed by his father after one lengthy drinking session with Mr Fujimoto, as too "girlish" to lead.
Long ago, the chef was certain who would be the heir to the world's only Communist ruling dynasty. "Jong-un will be his father's successor. Everyone used to say it. He looked and acted just like him".
Obsequiously, the chef only referred to the young Kim as "Prince". "When he shook hands with me, he stared at me with a vicious look. I cannot forget the look in the Prince's eyes: it's as if he was thinking: 'This guy is a despicable Japanese'."
Some have questioned whether, at 25, Kim Jong-un is too young to take charge and fend off challenges to his authority from the military. But his father purged his political rivals at the same age.
The younger Kim is thought to have studied at the International School of Berne in Guemligen, Switzerland, under a pseudonym before returning to a military academy in Pyongyang. There are varying reports that he can speak German, French and English. He has also been reported as overweight, diabetic, and possibly prone to health conditions in the wake of a car accident.
But his rise to power has been inexorable. In 2004, when he was 20, there were reports that he and his brother were joining their father on military inspections.
In 2007, a series of reports said he was working either in the Korean Workers' Party's powerful Organisation Guidance Department, where his father began his career in 1964, or in the army's General Political Bureau. Both departments are involved in surveillance and monitoring of the regime's highest officials.
Then, earlier this year, he appeared on the ballot for elections to the Supreme People's Assembly, the official North Korean parliament. He did not become an MP, but he was later given a post in the National Defence Commission.