Kim Yo-jong is one of former leader Kim Jong-il's seven children. She and current leader Kim Jong-un have the same mother, Ko Yong-hui. She's the only one of Kim Jong-un's siblings involved in government.
The younger Kim can be seen in glimpses on various North Korean news and propaganda videos. She's had a leading role in the Propaganda and Agitation Department and is said to be a close aide to her brother, planning his travel and public appearances, among other things.
Her new role as an alternate member of the country's top decision-making body means she can now participate in politburo debates but can't vote.
Kim Jong-un's sister joins his