Jin, the oldest member of K-pop mega-band BTS, has entered military service - the first of the group to do so.
The 30-year-old posted a photo of himself with his new military haircut before enlisting on Tuesday. "It looks cuter than I expected," he said.
As South Korea is still technically at war with its hostile neighbour North Korea, all able-bodied men are required to serve in the army.
BBC reports Jin has begun five weeks' training at a bootcamp near the North Korean border.
After this, he will reportedly be assigned to a frontline unit. This news sent his millions of adoring fans into a frenzy.
So, what can Jin expect from his time on the frontline?
At the Yeoncheon bootcamp, where Jin has enrolled, recruits sleep on mats on the floor, in rooms with 30 people. They are taught how to handle weapons and fire live ammunition before being put through demanding wartime scenarios.
Cadets told us that the most challenging tasks they faced were being sealed in a gas chamber, to experience the effects of CS gas, and having to detonate a live grenade.
"I was pretty nervous to hold the grenade and shocked to learn how powerful it was," said 22-year-old Yang Su-yeon, who completed his training at Yeoncheon last year.
"It was physically demanding, but mentally it was okay. The drill sergeants were all friendly," Yang said.
After training, Jin will reportedly be stationed near the North Korean border, with a frontline unit.
North and South Korea are separated by a 4km (2.5-mile) wide strip of land, which runs along the length of their border, known as the Demilitarized Zone (DMZ). Both sides are fenced off with barbed wire and heavily armed.
Yang spent his service as an out-post guard at the DMZ, with the 5th Infantry Division, which is one of the most frontline positions. He would keep watch through the night, constantly surveying the North Korean soldiers on the other side, using thermal imaging equipment.
"A few times I saw the North Korean soldiers being beaten, either kicked or slapped in the face," he said.
"They had to do manual labour because they didn't have nice equipment like us to help them."
Yang said watching the North Korean soldiers made him feel grateful for his own experience. "When I saw what they had to do, I realised, 'Wow, I am so much more comfortable.' I would feel sorry for them."
But BTS's Jin will have to contend with the cold winter approaching. Yang recalled days spent shovelling snow as temperatures fell below -20C.
"When we went outside, our eyelashes would freeze," he said.
Yang praised the culture of his unit: "Because we carried guns loaded with ammunition, we had to remain calm, so there was no harassment or beatings."
Yang volunteered to be deployed as a frontline guard, as this position comes with perks, including more time off base.
It is more likely Jin will be sent to a base set further back from the DMZ, like 26-year-old Heo Sungyoung, who spent his service with the 6th Corps Command Centre from 2018 to 2020.