kim yo jong north korea REUTERS/Damir Sagolj Kim Yo Jong, sister of North Korean leader Kim Jong Un, on April 13, 2017.

In a rare show of diplomacy between the two Koreas, Kim Jong Un's younger sister is traveling to South Korea on Friday for the opening ceremony of the 2018 Winter Olympics in Pyeongchang.

Her journey will be a milestone of historic significance - she'll be the first member of North Korea's ruling family to visit the south since the Korean War in the 1950s, according to The New York Times .

Like her brother, and much of the rest of their family, few details are known about Kim Yo Jong and the life she lived before reaching a prime leadership role in the North Korean government.

Here's what we know about her so far:

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Like many of Kim's family members, Kim Yo Jong's exact age is difficult to pin down. But she's believed to be between 29 and 31.

Like many of Kim's family members, Kim Yo Jong's exact age is difficult to pin down. But she's believed to be between 29 and 31.

She's the youngest child of former North Korean leader Kim Jong Il and his consort Ko Yong Hui, a former dancer.

She's the youngest child of former North Korean leader Kim Jong Il and his consort Ko Yong Hui, a former dancer.

Source: Business Insider

She was partly educated in Switzerland, at the same school Kim Jong Un attended. But she returned to North Korea in 2000 after completing the US equivalent of the sixth grade.

Source: North Korea Leadership Watch

It was clear from a young age that Kim Yo Jong was destined for a powerful career. Kim Jong Il once bragged to foreign interlocutors in 2002 that his youngest daughter was interested in politics and eager to work in North Korea's government.

It was clear from a young age that Kim Yo Jong was destined for a powerful career. Kim Jong Il once bragged to foreign interlocutors in 2002 that his youngest daughter was interested in politics and eager to work in North Korea's government.

Source: North Korea Leadership Watch

It's completely unclear, however, where she was or what she was up to between 2000 and 2007.

It's completely unclear, however, where she was or what she was up to between 2000 and 2007.

Source: North Korea Leadership Watch

In the following years, she conducted a lot of behind-the-scenes work for her father Kim Jong Il and brother Kim Jong Un. She played a particularly significant role in helping Kim Jong Un take over instead of his older brothers.

In the following years, she conducted a lot of behind-the-scenes work for her father Kim Jong Il and brother Kim Jong Un. She played a particularly significant role in helping Kim Jong Un take over instead of his older brothers.

Source: North Korea Leadership Watch

Her first public appearance was in 2011 at Kim Jong Il's funeral.

Source: The Washington Post

Kim Yo Jong made headlines last year after she was promoted to a top position in her brother's government: the head of the propaganda department of the Worker's Party of Korea.

Kim Yo Jong made headlines last year after she was promoted to a top position in her brother's government: the head of the propaganda department of the Worker's Party of Korea.

Source: The New York Times

That's not just a fancy title — Kim Yo Jong plays a crucial role in controlling her brother's public image.

Source: The Washington Post

In public, Kim Yo Jong appears to have greater freedom than other top government officials in North Korea, occasionally appearing in photographs unaccompanied rather than constantly being in the presence of Kim Jong Un.

In public, Kim Yo Jong appears to have greater freedom than other top government officials in North Korea, occasionally appearing in photographs unaccompanied rather than constantly being in the presence of Kim Jong Un.

Source: The New York Times

Some have speculated that she was promoted partly in an effort to continue Kim Jong Un's dynasty. While she's out of the line of succession, some believe she could take over the country's leadership if something happens to Kim Jong Un before his kids are old enough to rule.

Some have speculated that she was promoted partly in an effort to continue Kim Jong Un's dynasty. While she's out of the line of succession, some believe she could take over the country's leadership if something happens to Kim Jong Un before his kids are old enough to rule.

Sources: The New York Times, Washington Post

But in the Hermit Kingdom, no one's position is ever truly secure under the mercurial leadership of Kim Jong Un. He's known for turning on family members quickly when they fall out of favor — and it remains to be seen whether Kim Yo Jong is an exception.

But in the Hermit Kingdom, no one's position is ever truly secure under the mercurial leadership of Kim Jong Un. He's known for turning on family members quickly when they fall out of favor — and it remains to be seen whether Kim Yo Jong is an exception.