He's known around the world as the leader of North Korea, a ruthless dictator and a nuclear threat to Trump and the West.

But during the late 1990s, the now 34-year-old Kim Jong-un was known to his school friends as a child 'with a good sense of humour' that 'obsessed over basketball, especially the Chicago Bulls'.

From 1998 to 2000, North Korea's leader attended the Liebefeld-Steinhölzli public school in Koeniz, Switzerland.

A rare image of Kim Jong Il and his third son Kim Jong Un during his youth, Jong Un appears to be wearing Mickey Mouse ears. Jong Il was almost never been pictured with his daughters before his death in 2011 which caused Jong Un to come to power in the DPRK

During the time, while his father Kim Jong-il was reigning leader of North Korea, Kim Jong-Un was known to his school friends as 'Pak Un' the son of a staffer of the North Korean embassy.

He attended classes for non-German speaking pupils when he started at the school in the 1990s. A 2011 report said he was 'well-integrated, diligent and ambitious. His hobby was basketball.'

School friends also described Kim Jong-Un as having an enviable collection of Nike trainers, and despite being only 5'6" and 'slightly overweight' he was known as a 'good basketball player'.

He also loved playing with machinery and was a big fan of Michael Jordan.

Kim Jong-Un, pictured left as child, is described by school friends as 'a good laugh' and someone who 'loved basketball' particularly the Chicago Bulls and Michael Jordan (right)

Kim Jong-Un had previously been at a top private school, but despite having thousands of pounds lavished on his education he didn't leave with even the equivalent of a single GCSE.

Aged 15 his father took him out of the costly International School Of Bern, where fees now cost around £16,000 a year and moved him to a nearby state school to save money but he was quickly put in the lower tier in class.

Kim Jong Un took the empty seat in class next to Portuguese diplomat's son Joao Micaelo and the pair became friends.

Mr Micaelo who now works as a chef in a restaurant in Bern, said: 'We weren't the dimmest kids in class but neither were we the cleverest. We were always in the second tier.

He also described the dictator as a once 'good friend.'

Mr Micealo 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.'

When Kim Jong-un one day told Mr Micaelo who he was, he thought he was making it up.

Another classmate, Marco Imhof, from Bern, Switzerland described the supreme leader as 'funny' and 'always good for a laugh' but emphasised that he 'hated to lose' and 'winning was very important.'

Another former classmate said: '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'

'Politics were a taboo subject at school. We argued about football, not politics' German newspaper Welt am Sonntag, reported.

Kim Jong Un was one of five known children of Kim Jong-il. His older brother and younger sister, Kim Jong Chul and Kim Yo Jong also studied at private Swiss schools in the 1990s.

His older half-brother, Kim Jong Nam, who was famously assassinated with poison in Kuala Lumpur airport last year, studied in Moscow and Geneva.

School days: Kim Jong Un (circled) is pictured with friends during his time at school in Switzerland

Ko Yong Suk, Kim Jong Un's aunt on the maternal side acted as a guardian to Kim Jong Un and his two siblings during their school days in Switzerland.

Since 1998, Ko Yong Suk has been living an anonymous life in the US running a dry-cleaning store since defecting from North Korea.

'We lived in a normal house and acted like a normal family. I acted like their mother,' Ms Ko said about her time looking after the Supreme leader and his siblings, in a 2016 interview with The Washington Post.

'I encouraged him to bring his friends home, because we wanted them to live a normal life. I made snacks for the kids. They ate cake and played with Legos' she said.

Ms Ko added that Kim Jong un 'wasn't a troublemaker, but he was short-tempered and had a lack of tolerance.'

From 1998 to 2000, Kim attended the Liebefeld-Steinhölzli public school in Koeniz, Switzerland

Other pupils at the Liebefeld-Steinhölzli public school in Koeniz, Switzerland knew Kim as 'Pak Un' the child of an North Korean embassy worker

She added that he would not talk back to his mother when being told off, but protest in other ways like 'going on hunger strike'.

He reportedly showing signs of a complicated personality while in Switzerland and allegedly was once caught with a BDSM porn magazine.

This lines up with reports of a former bodyguard of Kim Jong-il, who described Kim Jong-un as 'stressed' and 'had no one to play with his own age' during his isolated childhood in North Korea.

Lee Young-guk told ABC news that Kim Jong-un had an 'explosive personality' and 'when he was angry, he acted without considering the consequences.'

Kim Jong-Un pictured on January 1 this year delivering a New Year's speech in North Korea

During holidays, Kim Jong-un was taken on skiing holidays to Italy, the Swiss Alps, and the French Riviera by his aunt.

While people believed the Kim siblings to be children of an embassy worker, they were known to be 'overprotected' which made 'people around them think it was bizarre' according to a 2011 report about the family.

In mid-2000, Kim returned to North Korea, but to his Swiss school mates he had vanished without a trace.

School sources say his father became fed up paying for an education that he thought was going nowhere. But it's also been speculated that his taboo love affair with American culture may have brought him back early.

The North Korean Embassy in Bern sent back reports on his son's friendships and influences to his father and intelligence chiefs back in North Korea.

Kim Jong Il (left) and Kim Jong Un (right) visit Mokran Video Company in Pyongyang in 2010

Mr Micaelo said: 'We spent nearly every afternoon with each other. He often invited me back to eat. He had a private chef who cooked whatever he wanted.

'Much of it wasn't to my taste. Lots of chicken in strange sweet-and-sour sauces. He didn't live at the embassy but in a flat in a nice residential area near the school.'

'He was surrounded by the best gadgets that the rest of us kids couldn't afford - TVs, video recorder, a Sony PlayStation. He had a cook, a driver, a private teacher.

'We spoke about girls and about our grand plans. At weekends there were parties and a lot of under-age drinking. But I never once saw a drop of alcohol pass his lips and he wasn't interested in girls.

'He only spoke about his life in the 'homeland' rarely. But I knew he had a certain homesickness. On his stereo he only played North Korean songs. Western music didn't do it for him.

It is believed he has not returned to the country in the 18 years since.

In 2011, Kim Jong-un succeeded his father, Kim Jong-il, as Supreme Leader when he died of a heart attack aged 70.

Kim Jong-un's time in Switzerland has thought to had an impact on his later life ruling North Korea.

A multi-million dollar Swiss ski resort that was built in North Korea in 2012.

Kim Jong-un inspecting a cosmetics factory in Pyongyang during his reign as leader of North Korea

The dictator oversaw the building of the Masikryong ski resort near Wonsan, Kangwon Province which is estimated to have cost somewhere between $35 million and $350 million (£25.3 million -£253 million).

But his attempt to buy Swiss ski lifts for the resort was thwarted due to international sanctions.

In 2013, he took over a large tract of land in Sepo, Kangwon Province and turned it into a pasture and an alpine farm, thought to be inspired by his time in Switzerland.

Kim Jong Un is also known to be fond of Swiss watches and has given them out to high-ranking officials in his party.