Yeoncheon, South Korea - Jin, the eldest BTS star, started his mandatory military service in South Korea on Tuesday, joining other new soldiers at a boot camp near the border with North Korea, according to multiple outlets.

Jin (30), whose full name is Kim Seok-jin, is the first member of BTS to begin 18 months of military duty, which is required by South Korean law for all eligible men between the ages of 18 and 35.

After speculation and public debate over whether the K-pop superstars would pursue an exemption to avoid military service, the group’s label, Bighit Music, announced in October that BTS members would be joining the army. The label said the artists will stagger their military service while they pursue their solo projects.

On Tuesday, Jin entered the Yeoncheon army base in northern Gyeonggi province in a motorcade of six black vans, where a few hundred fans gathered to show their support, CNN reported.

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Bighit Music said in a statement earlier this month that Jin would enter the base by car to prevent accidents and congestion, asking fans and media to avoid the area.

"We ask for your continued love and support for Jin until he finishes his military service and comes back," the label said. "Our company will also strive to provide every support he needs during this time."

Along with other new conscripts, Jin will take part in five weeks of basic military training at the base, including rifle shooting, grenade throwing, and marching practices, the Associated Press reported. He and other soldiers will then be assigned to army units across the country.

Mandatory military conscription in South Korea was established in 1957, shortly after the Korean War, to maintain a military force against North Korea.

Over the weekend, Jin posted a selfie on his Weverse social media account, showing off his new haircut, trading his black locks for a buzzcut. In a farewell tweet, the BTS members gathered for a photo with Jin, reaching their hands to touch his nearly bald head.

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"Our bro!! Have a safe service!! Love you," the tweet said.

Shortly after Bighit announced BTS’ military service in October, Jin dropped his first solo single, The Astronaut, which he co-wrote with British rock band Coldplay.