Alongside the country's leader Kim Jong Un, the girl -- likely Kim's second child Ju Ae -- inspected a guard of honour in the most recent of a slew of high-profile appearances that have sparked fervent speculation she has been anointed his heir.

AFP takes a look at what we know:

Who is she?

For years, North Korean state media never mentioned Kim's children, although Seoul's spy agency has said he has three with his wife. They are believed to be aged around 13, 10 and six.

The only previous confirmation of their existence had come from former NBA star Dennis Rodman, who claimed he met a baby daughter of Kim's called Ju Ae during a 2013 visit to North Korea.

But three months ago, at the launch of his most powerful intercontinental ballistic missile, Kim turned up with his "beloved" daughter in tow.

Although North Korea has never officially identified her by name, Seoul's spy agency and analysts believe the girl is Ju Ae, Kim's second child.

Is she Kim's heir?

It certainly looks that way, experts say.

State media has called her Kim's "beloved" and "respected" daughter, and she has been shown walking hand-in-hand with her father -- as her mother trailed behind them.

This indicates North Korea has started building a "personality cult" around Ju Ae, said Cheong Seong-chang, a researcher at South Korea's Sejong Institute.

It "signals that she has been designated as the de facto successor even though she doesn't hold the official 'successor' status yet", he said.

In state media images, Ju Ae has been placed in the middle, next to her father and surrounded by the country's top brass.

"It suggests that Kim Ju Ae will become the supreme commander of the military in the future," Cheong added.

Will North Korea accept a woman leader?

When it comes to women assuming political leadership roles, North Korea's glass ceiling has been bulletproof, says Bronwen Dalton, head of the department of management at the University of Technology Sydney's business school.

But change is afoot, she said, and North Korea's leadership is trying to "maintain its legitimacy by creating a new version of womanhood" that reflects social changes in the country over recent decades.

Younger generations have "grown up buying and selling in markets, using mobile phones and accessing foreign media content", which has forced North Korea to recalibrate its version of an ideal woman.

North Korea's current leadership, although predominantly male, does have some high-profile women, including foreign minister Choe Son-hui and Kim's younger sister Kim Yo Jong as a regime spokeswoman.

Kim Jong Un is "presiding over a propaganda apparatus forging a new narrative on the place of women", Dalton told AFP.

But crucially, the most important role of all North Korean women remains "devotion to their 'father' Kim Jong Un", which Ju Ae embodies perfectly, she added.

So she'll definitely be in charge one day?

Not necessarily, experts say.

"Perhaps more than any other country, relying on family ties and being in the proximity of power is precarious," Dalton said, pointing to a "revolving door" of family members who have been exiled from North Korea or killed.

"Women are not immune," she added.

A female leader remains "impossible" in North Korea for now, An Chan-il, a defector turned researcher who runs the World Institute for North Korea Studies, told AFP.

"No one would welcome the idea if Kim Jong Un disappeared right away and Ju Ae had to succeed him," he said.

But her gradual introduction to the public over the next decade or two, coupled with "ideological education", should help, he said.

"The North Koreans seldom question who becomes the ruler."

What about Pyongyang's nuclear arsenal?

While North Korea is not a monarchy, Kim Jong Un is the third generation of his family to rule the country, after his father and grandfather, founding leader Kim Il Sung.

For the Kims, one of the most important elements of regime preservation has been their nuclear and ballistic missile programmes.

"Celebrations of North Korea's nuclear-capable missile build-up may seem like strange occasions to project a child-friendly image," but they are effective domestic propaganda, Leif-Eric Easley, a professor at Ewha University in Seoul, told AFP.

"Kim is portraying Pyongyang's nuclear arsenal as a multigenerational asset to national security while proclaiming the military's complete loyalty to his political dynasty."