The wife of North Korea's Kim Jong-Un is a former singer who caught the leader's eye while she was giving a performance, South Korean media said Thursday after Pyongyang disclosed the marriage. Official media in the secretive state revealed late Wednesday that a stylish young woman pictured accompanying Kim this month is his wife, Ri Sol-Ju. It gave no details about her and did not say when they wed, but analysts said the mere fact that the couple were presented in public marked a new departure for the nation's dynastic leadership. The world has been scrambling for information about Jong-Un since he took over the impoverished but nuclear-armed state after his father Kim Jong-Il died suddenly last December. He is believed to be in his late 20s, but even his exact age is unknown outside the North. The International Crisis Group think-tank said in a report this week that Jong-Un appears to be fully in charge, despite speculation he would have to rely on close advisers because of his youth and inexperience. But it said there was nothing to suggest he would take measures to improve the lot of his people amid severe food shortages, or reduce regional frictions over the North's nuclear and missile programmes. In public, Jong-Un has presented a relaxed and confident image in an apparent attempt to emphasise his readiness to rule. In contrast to his late father, he has cultivated an outgoing and informal style -- hugging soldiers, posing for photos with troops and linking arms with women. Neither his father nor grandfather Kim Il-Sung were ever pictured with their wives at public events. But the disclosure of Jong-Un's marriage is partly to show "he is not a child", said Chang Yong-Suk, of the Institute for Peace and Unification Studies at Seoul National University. "If he went around alone, people would look down on him as a young lad, but with his wife present, he could show he is the head of the family and also an adult," Chang told AFP. South Korean media reports generally agreed that the short-haired and smiling woman, apparently in her twenties, is a former songstress who was specially trained to become Kim's consort. Yonhap news agency said she could be seen singing on video footage of a performance released by the North in February last year. Ri had taken a six-month course in the duties of a first lady, the agency said. Chosun Ilbo newspaper said Ri was active in the North's Unhasu orchestra until last year and had performed for Jong-Un and his father on New Year's Eve 2010. "There is a possibility Jong-Un chose her as his wife after seeing her at the concert hall," it quoted a source as saying. Another source told the paper that after the marriage Ri had undergone a six-month course in duties of a first lady at Kim Il-Sung University, the nation's most prestigious academic institution. JoongAng Ilbo also described Ri as a former singer who came to the young Kim's notice during a performance. It said Jong-Un's father had singled her out as first lady while he was working on his succession plan. The Kim Il-Sung University graduate is from the northeastern province of North Hamkyong whose father is an academic and mother a doctor, the paper said. Dong-A Ilbo gave similar details about her background and said the couple married in 2009. The United States took the opportunity to reiterate concerns about the plight of North Koreans under the Kim family dynasty. "We would always wish any kind of newlyweds well as they embark" on married life, said State Department spokeswoman Victoria Nuland, joking that the United States had not been invited to the wedding. "But obviously our concerns first and foremost are for the North Korean people, and our hope that conditions for them will improve."