Kim Jong-un’s former classmates struggle to reconcile their memories of the “good friend” who was obsessed with basketball with the North Korean dictator.

According to friends he made while studying at a German-speaking public school near Bern, Switzerland, the head of the rogue state had a good sense of humour and an impressive collection of Nike trainers.

“He was a good friend,” Joao Micaelo, who now works as a chef at a restaurant in Bern, told The Daily Beast.

“We had a lot of fun together. He was a good guy. Lots of kids liked him. I don’t know anything about his life today. All I know is the guy I knew in school.

“He loved basketball. We played a lot together. I’d like to say to him, if you ever have the time, please contact me again so we can catch up.”

Dennis Rodman sings Kim Jong-un Happy Birthday on 8 January- the date widely believed to be the North Korean leader's birthday

At school, he was called “Pak Un” and described as the son of an employee at the North Korean embassy.

The future North Korean despot was said to be especially enthusiastic about the Chicago Bulls and a good basketball player, despite being only 5ft 6in tall and slightly overweight.

“He was funny,” another former classmate, Marco Imhof, told the news site. “Always good for a laugh. He also hated to lose. Winning was very important.”

Other classmates agreed. “He had a sense of humor and got on well with everyone, even those pupils who came from countries who were enemies of North Korea,” one told German newspaper Welt am Sonntag.

“Politics was a taboo subject at school... we would argue about football, not politics.”

Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb Show all 6 1 /6 Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb Photos released by North Korea show Kim Jong-un talking to subordinates next to a device thought to be the new thermonuclear weapon. There is no way of independently verifying the pictures STR/AFP/Getty Images Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb North Korea claims it has successfully tested an advanced hydrogen bomb which could be loaded onto an intercontinental ballistic missile AFP/Getty Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb A diagram on the wall behind Mr Kim shows a bomb mounted inside a cone STR/AFP/Getty Images Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb North Korean leader Kim Jong-Un (C) attending a photo session with participants of the fourth conference of active secretaries of primary organisations of the youth league of the Korean People's Army (KPA) in Pyongyang STR/AFP/Getty Images Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb A new stamp issued in commemoration of the successful second test launch of the "Hwasong-14" intercontinental ballistic missile KCNA via Reuters Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb A new stamp issued in commemoration of the successful second test launch of the "Hwasong-14" intercontinental ballistic missile KCNA via Reuters

A former bodyguard for his now-deceased father, Kim Jong-il, said an isolated childhood left Kim Jong-un “stressed” and “explosive.”

“He was stressed and had no one to play with his own age,” Lee Young-guk told ABC News. “There were only adults, who educated and played with him.”

Mr Lee, who was one of the elder Kim’s bodyguards for 11 years, said: “His personality was explosive. When he was angry, he acted without considering the consequences.”