Barely two weeks since his father's death, North Korea's untested new ruler has already accumulated an impressive array of new titles, including "supreme commander", as he tightens his grip on power.
The enigmatic son who has inherited the world's last communist dynasty while still in his late 20s has taken a step out of the shadows to lead the mourning for longtime leader Kim Jong-Il, whose funeral was being held Wednesday.
The North's propaganda machine has cranked up to rally support for Kim Jong-Un, the Swiss-educated youngest son of the late dictator, heaping praise on the "tender-hearted" successor.
The secretive state has been quick to burnish the credentials of the new leader, hailing him as head of the powerful military as well as chief of a key ruling party organ.
Experts say the proclamations leave little doubt that Jong-Un is on track to take full control of the secretive nation, even if he is expected to initially rely on a coterie of powerful aides, including his uncle.
"For the first few years, because he's so young and inexperienced, the actual policy will be decided by the people who used to be advisers of his father," said professor Andrei Lankov of Seoul's Kookmin University.
"He (Jong-Un) will be a kind of figurehead, a presiding figure. Whether he will emerge as a real dictator or whether he will choose to remain a figurehead, we don't know," Lankov told AFP.
The new leader's life is shrouded in mystery. But in recent years he has been pushed to the forefront as his father speeded up plans for the nation's second dynastic succession, after suffering a stroke in August 2008.
In September 2010 the son was made a four-star general and given senior ruling party posts, despite his lack of any military experience.
It was only then that state media published his first-ever adult photograph -- an image of a chubby young man dressed in a dark Mao-type suit sitting in a line-up of top communist party officials.
Since his father's death he has been shown on the North's official television many times, weeping in front of his father's body as it lies in state and receiving mourners.
In a memoir, Kenji Fujimoto, a former Japanese sushi chef for Kim Jong-Il, described Jong-Un as a "chip off the old block, a spitting image of his father in terms of face, body shape and personality".
But with a new short-back-and-sides haircut and a rotund figure, he now bears a striking resemblance to his late grandfather Kim Il-Sung, the founder and "eternal leader" who is still revered by many North Koreans.
Jong-Un has also entered the diplomatic arena, meeting the leaders of two South Korean delegations at the Kumsusan Memorial Palace, including former first lady Lee Hee-Ho.
Following his 2010 elevation, Kim Jong-Un was constantly at his father's side, and is said to be actively involved in state affairs.
Jong-Un has made headlines since his name was floated by South Korean media in early 2009 as the figure being groomed to succeed his father.
South Korea's spy chief said last year that Kim Jong-Il's poor health had driven him to speed up preparations for the transfer of power, with the son taking a bigger policy-making role and accompanying his father on trips.
Some analysts had earlier seen second son Kim Jong-Chul as favourite to take over. But Fujimoto said in his memoir that Kim thought of Jong-Chul as effeminate and unfit for leadership.
Eldest son Jong-Nam apparently spoiled his prospects after being deported from Japan in 2001 for trying to enter with a forged passport while attempting a visit to Tokyo Disneyland.
Jong-Un was born to the leader's third wife, Japan-born ethnic Korean dancer Ko Yong-Hi, who is believed to have died of breast cancer in 2004.
He is believed to have studied in Switzerland under a false name.
Reports say he enjoyed basketball and drawing cartoons at international school, where staff and friends remembered a shy boy who liked skiing and Hollywood tough guy Jean-Claude Van Damme.