North Korean leader Kim Jong-un's wife Ri Sol-ju appears in public more frequently as North Korea's first lady, but intelligence officials believe she faces considerable pressure to consolidate her position.

"She's probably experiencing some anxiety over the possibility of being abandoned like Song Hye-rim," former leader Kim Jong-il's wife.

Song Hye-rim (left) and Ko Yong-hui

Song was one of North Korea's best-known actresses when she began living with Kim Jong-il in the late 1960s and gave birth to his eldest son Jong-nam. She used to be the wife of South Korean writer Lee Ki-young, who defected to North Korea. But Kim fell in love with her at first sight and practically snatched her away.

However, in 1973 Song's health deteriorated rapidly. Song's elder sister, Song Hye-rang, who defected to the West, said, "She became ill because she was afraid that her son would be taken away from her." Kim Jong-il dumped Song when he fell in love with dancer Ko Yong-hui and began living with her in 1979. Ko is Kim Jong-un's mother.

Suffering from depression, Song moved from one country to another until she died in Moscow in 2002.

Ko reigned as North Korea's first lady until her death in 2004 after giving birth to Jong-chol (32), Jong-un (28) and Yeo-jong (25). Though she was never seen in public, her status became even stronger after Jong-nam fell out of favor with his father in 2001 and lost his chance to succeed him. Ko's firmest supporters were party heavyweights like Ri Je-gang and Ri Yong-chol.

Kim Song-ae, nation founder Kim Il-sung’s second wife, sowed dissent and fought bitterly with Kim Jong-il, recalls a former high-ranking North Korean official. "Ri is a potential source of instability in North Korea."