No one seems to know the woman's identity, and one expert on North Korea says no one likely will find out, CNN reported Tuesday.
"Everything related to Kim Jong Il's children is a deadly secret. No sane North Korean who knows it would share this out for very special reasons," said Andrei Lankov of Kookmin University in South Korea, an expert and author of several books on North Korea.
The woman -- speculated to be a sister, girlfriend or wife -- accompanied Kim to a Pyongyang theater Friday for a performance of North Korea's Moranbong band, CNN said. She also was seen on state television Sunday walking a few steps behind Kim as he toured Kumsusan Palace, then standing at attention by Kim's side during a tribute to his grandfather Kim Il Sung, North Korea's founder.
The presence of a woman accompanying him to an official engagement was unusual, Lankov said, and could be part of a campaign to show Kim is "much more approachable, human-like and soft on people" than his father, Kim Jong Il.
"He travels much more than his father and even than his grandfather. He likes to hug everybody, physically hug. In this regard it's probably he decided that it might be a good idea to hint that he does have a wife," Lankov added.
The South Korean daily Chosun Ilbo reported the woman "seemed to be" Kim Jong Un's sister, Kim Yeo Jung.