North Korea’s mysterious diplomat: Kim Yong Chol, the man meeting Donald Trump

Donald Trump confirmed a June 12 summit with North Korea’s Kim Jong Un directly after meeting with a former North Korean military spy chief and one of Kim Jong Un’s most trusted aides.

READ MORE: Donald Trump confirms June 12 meeting with Kim Jong Un

Kim Yong Chol is the highest-ranking North Korean official to visit the U.S. in 18 years, and his trip to the White House to deliver a letter from Kim Jong Un will be a highly symbolic sign of easing tensions after fears of war escalated amid North Korean nuclear and missile tests last year.

Kim was also allowed into the United States despite being on a U.S. sanctions list. So how did this mysterious diplomat land a key role in helping ease tensions between the two nations?

WATCH: North Korean official returns to hotel after meeting with Mike Pompeo

Kim Yong Chol, the controversial figure

The North Korean official has served three generations of the Kim dynasty and in recent months emerged one of the most powerful figures in Kim Jong Un’s regime.

He is no relation to the Kim Jong Un.

He’s also a four-star general and vice chairman of the ruling Workers’ Party’s Central Committee. As director of the United Front Department, he steers Pyongyang’s relations with South Korea.

READ MORE: U.S. intelligence builds profile on secretive leader, Kim Jong Un, ahead of Trump meeting

Kim is thought to be around 72 years old and has a reputation as a difficult negotiator; he reportedly once stormed out of a room during talks with Seoul.

“He wears several hats,” Duyeon Kim, a senior research fellow at the Korean Peninsula Future Forum think tank, told the Guardian. “He is extremely well versed in denuclearization matters, and seems to have secured himself a spot in Kim Jong Un’s inner circle.”

He is also a very controversial figure.

Kim was accused by Seoul of planning deadly attacks on a South Korean navy ship and an island in 2010, that killed 46 sailors. He was also linked by U.S. intelligence to a cyberattack on Sony Pictures in 2014.

North Korea denied involvement in both incidents.

In early 2012, Kim lost one of his four stars and was demoted to colonel general before earning it back, apparently within a month.

WATCH: North Korea envoy leaves New York hotel ahead of expected meeting with Trump in Washington

Now he plays a key role in the easing of relations between the two Koreas and with the United States following months of belligerent rhetoric between Trump and leader Kim.

In February, the four-star general was part of the North Korean delegation at the closing ceremony of the Olympics in Pyeongchang, South Korea. He was seen sitting behind Ivanka Trump during the event.

Kim played a role, along with South Korean intelligence chief Suh Hoon, in arranging a surprise meeting in April between U.S. Secretary of State Mike Pompeo and Kim Jong Un in North Korea.