When he boarded a train in Pyongyang three days earlier, Korean Central Television showed him with his hair parted in the middle.

His hairstyle remained unchanged at Nanning station in China in TBS News photos.

But when he arrived in Vietnam, his hair was combed backward and gelled neatly.

Kim has always appeared in public with undercut hair called paeki in Korean.

Experts say he wants to look like his grandfather and the founder of North Korea, Kim Il-sung.

Kim's hairstyle is very popular in North Korea among both young and middle-aged people. Men are encouraged to pay homage to the leader by copying his hairstyle, Chosun Ilbo, a South Korean newspaper, claimed.

Kim became his country's leader at a young age and so North Korean youths want to copy his style just like other young people around the world, who imitate the looks of celebrities they idolize, Kang Dong-wan, a professor at Dong Ah University in Busan, South Korea, said.