Years of tension have made these two countries apart due to the North's nuclear program.
Red Velvet member Seulgi said she cried when North and South Koreans together sang "Our Wish is Unification".
The North Korean leader appeared in a group photograph with the performers, distributed by North Korean media. "Having invited South Korean journalists to the North, we have a duty to ensure that you can gather news freely and film comfortably", Kim was quoted as saying.
The North is planning to hold a major parliamentary meeting on April 11, in which the country's rubber-stamp parliament, the Supreme People's Assembly, usually makes critical decisions on spending, legal revisions and personnel reshuffles at state organs.
The performance coincided with the beginning of annual joint South Korean-U.S. military drills, which have previously been met with denunciations and missile launches by the North. I had initially planned to attend a performance the day after tomorrow but I came here today after adjusting my schedule. "If that moves North Korean citizens' hearts and the two relationships get a little better through music, I think that's what we can do", he said.
Kim arrived 10 minutes before the concert started and was greeted by the South Korean delegation including Culture Minister Do Jong Hwan and musical director Yun Sang.
All of that is leading up to a May meeting between President Donald Trump and Kim Jong-un. The North Korean leader was confusing everyone with his actions and words. It was all part of a reciprocal cultural visit since North Korea sent performers in February to its southern neighbor. There will be another event on Tuesday that will showcase the talents of South Korean acts.More news: Kosovo to investigate extradition of Turkish nationals
It was the first time a North Korean leader personally attended a South Korean concert, and Kim showed up with his wife Ri Sol-ju at the East Pyongyang Grand Theatre.
Rock band YB performed next follows by K-pop girl group Red Velvet and then a performance by Choi Jin Hee - who is visiting the North for the fourth time - and Lee Sun Hee took place.
"(Kim) expressed thanks to them for coming here with (a) good performance, prepared by them with sincerity in a short span of time", the KCNA report said.
The Pyongyang government at the beginning of this year opened the way to a succession of talks with South Korea where reciprocal trips of high officials were consensuated, the presence of the North in the sports venue and the performance of artists in both territories.
Kim has also deployed his family, including Ri and his sister, Kim Yo Jong, to soften his and his country's image.
His welcoming of K-pop icons, and Kim Yong-chol's apology, are a stark departure from just a few years ago, when South Korea began blaring K-pop songs across their shared border as a psychological warfare tactic.
South Korean groups perform during a rehearsal in Pyongyang on Sunday. Kim praised the group, who has more than 4.6 million Instagram followers, for their wonderful performance as well as asked the art troupe, which consists of 160 members from different entertainment field, to extend his appreciation to South Korean President Moon Jae-in for a wonderful concert.