Kim Jong Un's sister makes first appearance since 'mysterious' daughter chosen as future leader

Kim Jong Un's sister has made her first public appearance since the North Korean Supreme Leader's 'mysterious' daughter was reportedly chosen as the nation's future leader, according to South Korea’s intelligence service.

South Korean officials believe his daughter, Kim Ju Ae, thought to be 13, is being prepared to take over in the future and, if confirmed, she would become the country’s first female ruler.

The National Intelligence Service told lawmakers in a private briefing earlier this month (12 February) that the teenager, previously described as being 'trained' as a successor, had now reached the stage of 'successor designation'.

"In the past, (NIS) described Kim Ju Ae as being in the midst of ‘successor training’. What was notable today is that they used the term ‘successor-designate stage’, a shift that's quite significant," lawmaker Lee Seong-kwen said.

He added: "As Kim Ju Ae has shown her presence at various events, including the founding anniversary of the Korean People's Army and her visit to the Kumsusan Palace of the Sun, and signs have been detected of her voicing her opinion on certain state policies, the NIS believes she has now entered the stage of being designated as successor."

Kim Jong Un's sister has made her first public appearance since his daughter was reportedly as his heir (STR / Contributor / Getty Images)

The agency said its conclusion is based on several factors, notably her rising profile at official events. The teenager attended North Korea's party congress this week.

State media in Pyongyang haven't published her name, referring to her only as Kim Jong Un’s 'respected' or 'most beloved' child. Her exact age is unconfirmed, though South Korean intelligence believes she was born in 2013.

She is the only child of Kim Jong Un and his wife, Ri Sol Ju, to have been publicly identified. The NIS has also suggested he may have an older son, though no such child has appeared in state media.

"Although the South Korean spy agency now believes Ju Ae is the designated heir, it still raises questions," the BBC reports.

Kim Ju Ae, who is reportedly around 13 years old, is the only child of Kim Jong Un and his wife, Ri Sol Ju (KCNA VIA KNS / AFP via Getty Images)

"It is puzzling why Ju Ae, a daughter, would be selected as the heir above an older son in North Korea's deeply patriarchal society. However, it is also a mystery why Kim Jong Un, who is still young and appears relatively healthy, is already designating a 13-year-old child as his heir now."

Kim Jong Un's sister, Kim Yo Jong, has now been seen publicly for the first time since being sidelined as a potential heir to her brother, Kim Jong Un.

While South Korean intelligence believes that teen Kim Ju Ae has been 'designated as successor', Kim Yo Jong is expected to take on a powerful but separate position, the Mirror reports.

Kim Yo Jong also recently attended the week-long Ninth Congress of the Workers' Party of Korea, where she accepted a prominent new role.

She was appointed a full department director at the Korean Central News Agency, the regime’s main propaganda outlet.

Kim Jong Un's sister, Kim Yo Jong, is expected to take on a powerful but separate position (VLADIMIR SMIRNOV / Contributor / Getty Images)

South Korean media suggest she could oversee inter-Korean affairs and broader external strategy.

Analysts say the promotion strengthens Kim Jong Un’s grip on government while keeping his sister, who reportedly holds strong backing within the military, firmly inside the inner circle.

North Korean defector and scholar Ahn Chan-il said she is among the few people the leader 'can trust and rely on'.

He told AFP: "Kim Yo Jong is one of the very few people that Kim Jong Un can trust and rely on."

Kim Yo Jong has previously held senior posts, including deputy department director in the propaganda apparatus.