Like father, like son
North Korea's leader Kim Jong-il died in late December. Little is known about Kim Jong-un, his youngest son and chosen heir. Until 2009, Kim Jong-un had not been known to hold any formal office in the North Korean government.
Because of his youth and inexperience in a country which traditionally values seniority, Kim Jong-un is seen to be ill-suited to fill his father's shoes.
For a while foreign analysts believed it was his half-brother Kim Jong-nam or older brother Kim Jong-chol who would take over leadership in the secretive dictatorship.
Yet his brothers' embarrassing behaviour meant Kim Jong-un was designated as heir to his father.
Kim Jong-nam was deported from Japan in May 2001 for trying to get into the country on a forged Dominican passport.
He told immigration officials he wanted to go to Tokyo Disneyland.
Kim Jong-chol, meanwhile, was seen by his father as too weak to take over, according to Japanese chef Kenji Fujimoto, who had worked for Kim Jong-il for more than 20 years before fleeing North Korea in 2001. Fujimoto published his memoirs I was Kim Jong-il's Chef in 2003.
To help establish Kim Jong-un as the new ruler, North Korea's state media has hailed him as 'supreme commander' of the country's massive armed forces.
'We will uphold Comrade Kim Jong-un as our supreme commander and general and we will bring the revolution to a completion,' the ruling Communist Party's Rodong Sinmun newspaper said in an editorial on December 31.
It is the first time one of the country's media outlets have used the title 'supreme commander' - a post previously held by Kim Jong-il - for the new leader, who was earlier made a four-star general.
Is Kim Jong-un ready to lead?
A 5,000-word editorial carried by KCNA, North Korea's state news agency, called on North Koreans to rally behind their new leader Kim Jong-un. It urged them to protect him as 'human shields'. It also told them to solve the 'burning issue' of food shortages by upholding the policies of the late Kim Jong-il.
'Kim Jong-un, the supreme leader of our Party and our people, is the banner of victory and glory of Songun [military-first] Korea and the eternal centre of its unity,' it said.
Kim Jong-un was officially appointed supreme commander of the North's 1.2-million-strong military shortly after his father's death. Yet foreign observers point out that he's untested and has been groomed for power only since 2009.
Kim Jong-un will rule with the aid of a close group that includes his uncle and key officials.
Former US assistant secretary of state Christopher Hill, who led the US delegation in six-party nuclear talks on North Korea, told BBC news he believed Kim Jong-un was 'not ready' to take the helm. 'There are a few more years to go before he can be considered a real player,' he said. 'Right now the military and Jang Song-thaek, the brother-in-law of [the late] Kim Jong-il, have a lot to say. It is unclear at this point who will emerge with real leadership.'
How will change in leadership impact international relations?
Reuters reported from Seoul that momentum was building in diplomatic contacts between North Korean and the United States before Kim Jong-il's death. The meetings were aimed at restarting stalled talks about ending the North's nuclear programme.
Those talks stalled in 2008 when Pyongyang prevented inspections of its nuclear sites under a 2005 deal by six countries [the two Koreas, the United States, China, Japan and Russia]. The North was to receive aid in return for disarmament.
'By [yielding] on the nuclear issue, the North would secure much room in negotiations with the United States and the other signatories of the six-party talks,' said Yang Moo-jin, a professor at Seoul's University of North Korean Studies.
Yet last week, in the first bit of communication from the North with the outside world since Kim Jong-il's death, the country's National Defence Commission declared it would not deal with the current government in the South.
South Korean President Lee Myung-bak angered Pyongyang by cutting off aid when he took office in 2008. He was demanding nuclear disarmament and economic reform as preconditions to restart food assistance.
Tensions on the divided peninsula reached a new peak in 2010 when the North launched an artillery barrage into a South Korean island, killing civilians. The North was also blamed for a torpedo attack against a South Korean navy ship that killed 46 sailors.
North and South Korea are technically still at war under a truce that ended the 1950-53 Korean War.
Getting to know Kim Jong-un
Kim Jong-un was born in 1983 or early 1984. He is the youngest son of Kim Jong-il and his late third wife Ko Yong-hui, who is thought to have been Kim Jong-il's favourite wife. Kim Jong-un's mother used to call her son the 'Morning Star King'.
Kim Jong-un was educated in Switzerland's International School of Berne. It is a boarding school favoured by the Kim clan and other members of the tiny Pyongyang elite.
Students and school staff described him as a shy boy who liked skiing and basketball and mixed with a range of children of different nationalities, including those of US diplomats. He learned French and German. The Swiss weekly L'Hebdo reported that he used the name Pak Chol and pretended to be the son of the North Korean embassy's driver.
He returned to Pyongyang when he was 15 to attend Kim Il-sung Military University.
Rise to power
Many observers believe Kim Jong-il chose his youngest son to succeed him because of the poor performance of his half-brother Kim Jong-nam and older brother Kim Jong-chol. Yet there is speculation he may have been anointed successor partly because of his resemblance to North Korea's founder Kim Il-sung. There were rumours that Kim Jong-un had undergone plastic surgery so that he would more closely resembles his grandfather.
Kim Jong-un made his first public appearance when he was appointed a four-star general last year. He has been assigned two significant posts: membership on the Central Committee of the Communist Party and vice-chairmanship of the Central Military Committee.
South Korean media reports say Kim Jong-il's brother-in-law, Jang Song-thaek, has been appointed as a mentor to Kim Jong-il to ensure a smooth transition.
In line with the god-like reverence shown to his father and grandfather, the young Kim Jong-un's birthday on January 8 will be made a national holiday.
Japanese chef Kenji Fujimoto, who served Kim Jong-il for more than 20 years, described Kim Jong-un as a 'chip off the old block'.
Fujimoto said Kim Jong-un shares his father's tastes for fine food, including shark's fin soup three times a week, and plenty of tuna, washed down with cognac.
'Kim Jong-un knows how to be angry and how to praise. He has the ability to lead people,' Fujimoto said. 'He also loves basketball, rollerblading, snowboarding and skiing and is a fan of US basketball legend Michael Jordan.'
Yet it is believed Kim Jong-un also shares some of his late father's health problems, including diabetes.
What people are saying
'He [Kim Jong-un] is going to be loyal to his father. He is going to be obedient to his elder brothers,' Leonid Petrov, an expert on North Korea at The Australian National University in Canberra, told broadcaster Al Jazeera.
'I think in Kim Jong-un we are going to see someone who is prepared to look beyond the borders of North Korea and there may be a new page. The problem is ... will the West respond?' noted Larry Jagan, an expert on Asia.
'That's what was so special about Dad, you know. He never worried about all that stuff, he just acted like himself. What can I say? The old man set the loony bar pretty high. God, I'm really going to miss him, you know?' the satirical online newspaper The Onion joked about what Kim Jong-un himself might say.