Seoul, South Korea (CNN) North Korea leader Kim Jong Un, accompanied by his wife Ri Sol Ju, clapped and waved Sunday as he attended a rare concert of South Korean singers and performers in Pyongyang.

After the two-hour plus concert, the North Korean leader and his wife shook hands with the pop stars, that included K-pop girl band Red Velvet, and took pictures with them, according to video and press pool reports.

The concert marked the first time in over a decade that South Korean musicians have traveled to North Korea, as relations between the two countries have thawed ahead of a groundbreaking summit of the leaders of the two countries planned for the end of April.

This April 1, 2018 picture released from North Korea's official Korean Central News Agency (KCNA) on April 2, 2018 shows North Korean leader Kim Jong-Un and his wife Ri Sol-Ju posing with South Korean musicians after a rare concert.

The young North Korean leader "was deeply moved to see our people sincerely acclaiming the performance, deepening the understanding of the popular art of the south side," according to North Korea state news agency KCNA.

Before her marriage to Kim, Ri Sol Ju was a singer in the North Korean Unhasu Orchestra, South Korea's Unification Ministry has confirmed, and videos of her performance can be found online.

A South Korean lawmaker told CNN in 2012 that "Ri was partially educated in China and visited South Korea in 2005 for the Asian Athletic Championships "as a member of North Korea's cheering squad."

KCNA reported that Kim had enjoyed Sunday's concert -- something that surprised some observers in Seoul given that it has been a punishable crime for North Koreans to consume South Korea popular culture including music, movies and soap operas.

In previous years K-pop, which has a global following, has been used by Seoul in a very different capacity.

In early 2016, following a North Korean nuclear test, the South blasted its northern neighbor with giant speakers playing propaganda and music across the heavily militarized border.

North Korean leader Kim Jong-Un speaks to South Korean musicians after the concert, in this photo released from North Korea's official Korean Central News Agency (KCNA).

Audience sings along

Speaking after the performance, Red Velvet members said that they'd been surprised by the warm reception.

"The applause was much louder than we thought," Red Velvet singer Kim Ye-rim, whose stage name is Yeri, told South Korean reporters, while bandmate Wendy, real name Son Seung-wan, admitted that that had "expected the worst" response to the show.

"We were on stand-by and watching when (fellow K-pop act) YB was performing, we saw the audience singing along," Yeri said. "So that helped us relax."

The band members added that the would like to return to the capital if they were invited again.

South Korean girl band Red Velvet is seen after their performance in Pyongyang, North Korea, Sunday, April 1, 2018.

"Everyone had a smile on their face. So that gave us strength," said Kang Seul-gi, another Red Velvet singer, who performs under the name Selgui. We hope we can have more exchange through this event so more of our songs can be known."

Sunday's performance was one of two scheduled during the trip. The next one will be on Tuesday.

"(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.

"He said that as he may have no time because of his complicated political program early in April, he came to enjoy the performance of the south side art troupe he invited to visit here."

K-pop began in South Korea in the early 1990s, with homegrown labels building the nation's pop industry from the ground up and creating a global entertainment force known for its splashy music videos, dance routines and style.

Pyongyang residents enjoy a rare concert by South Korean musicians at the 1,500-seat East Pyongyang Grand Theatre in Pyongyang in this photo released from North Korea's official Korean Central News Agency (KCNA).

Leading North Koreans attended show

Also in attendance from North Korea were Kim's sister Kim Yo Jong, North Korea's ceremonial President Kim Yong Nam, along with other members of the regime, including Choe Hui, Ri Son Gwon and Kim Chang Son, according to the pool.

In addition to K-pop girl band Red Velvet, starlet Seohyun of Girls' Generation, singers Cho Yong-pil and Lee Sun-hee, and rocker Yoon Do-hyun were among those who traveled north of the demilitarized zone (DMZ) -- the heavily fortified border dividing the two Koreas -- for two concerts in the North Korean capital.

Pyongyang residents watch the performance at the East Pyongyang Grand Theatre in Pyongyang in this image released by KCNA.

Yoon, who also performed in Pyongyang in 2002, recently explained to CNN his reason for performing.

"We go as something similar to a cultural mission and do the performance diligently. 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.

On Yoon's first visit to the North Korean capital, he told CNN, one of his band members was almost stopped from playing.

"Our guitarist's hair was yellow," the South Korean rock star told CNN. "The North Koreans talked about that hair and said that he could not perform with it ... it wasn't easy from the beginning!"

Separately, the South Korean taekwondo team performed at the Pyongyang Taekwondo Hall as North Korean officials and residents watched.

Diplomatic thaw

The concerts and sports demonstration come after a period of diplomatic thaw between the two nations, which began after South Korean President Moon Jae-in, who favors closer ties with Pyongyang, entered office in May 2017.

Kim made conciliatory comments towards the South during his New Year's speech, and followed up by re-opening a diplomatic phone hotline between the two neighboring countries.

JUST WATCHED South Korean stars prepare to rock Pyongyang Replay More Videos ... MUST WATCH South Korean stars prepare to rock Pyongyang 02:45

In February, North Korean athletes and entertainers, along with a retinue of political figures, attended the 2018 Winter Olympics, hosted by South Korea, after which a senior delegation from Seoul traveled north for meetings with Kim.

During that meeting Kim extended an offer to meet with US President Donald Trump, which was accepted.

Despite the rapprochement, annual joint US-South Korea military drills, codenamed Foal Eagle, kicked off on Sunday. The drills, which have long drawn the ire of Kim, are expected to last for four weeks -- shorter in duration than in previous years.