The younger sister of North Korean leader Kim Jong-un was married last year to a son of Choe Ryong-hae, one of the closest aides to Kim, sources said Friday.

"As far as I know, Kim Yo-jong, deputy director of the Workers' Party, got married to a son of the party's secretary Choe Ryong-hae," said a reliable source based in China.

Choe is known to be the most powerful official in the communist nation behind leader Kim.

Choe has two sons and a daughter, according to another source.

The second son, Choe Song, is her husband, added the source. He is reportedly in his early 30s, but his job title has not been confirmed yet.

Earlier Friday, the North's media released a photo of Kim Yo-jong, 28, who accompanied her brother in a visit to a Pyongyang orphanage on New Year's Day.

It showed her wearing what appears to be a wedding ring on the ring finger of her left hand. (Yonhap)