Ever wonder what it is like to go to school with the son of North Korea's reclusive leader? Marco Imhof knows.

Imhof says he attended school in Switzerland with Kim Jong-un, the youngest son of Kim Jong-il, and claims there was a fair amount of "trash talk," or insulting fellow competitors, when they played basketball together.

Al Jazeera's exclusive report reveals that among a group of teenage students, one boy, who went by the name "Pak Un", had an extraordinary secret - the future heir to one of the world's most secret governments.

Imhof underlines the normality of the early years of a man who may assume one of the most powerful positions in the world.

Little is known about the children of Kim Jong-il, but information has been trickling out since early last year when the first signs emerged that Kim Jong-un was being groomed for the leadership.