Members of K-pop group NCT send off Jaehyun (fourth from the left) as he starts his mandatory military service. Photo from NCT's X accountMembers of NCT gathered on Monday to bid farewell to their bandmate Jaehyun as he enlisted in the military, making him the second member of the K-pop boy group to start his mandatory service.

On its X (formerly Twitter) account, NCT shared photos of members Johnny, Doyoung, Ten, and Jungwoo sending off Jaehyun, along with Taeyong, who was the first NCT member to enlist last April.

Members of K-pop group NCT send off Jaehyun (fourth from the left) as he starts his mandatory military service. Photo from NCT's X accountPhoto from NCT's X accountA day prior to his enlistment, the 27-year-old idol took to Instagram to post photos his buzz cut.

Photo from Jaehyun's Instagram account

Photo from Jaehyun's Instagram account

Photo from Jaehyun's Instagram accountSouth Korea requires all able-bodied men under 30 to serve at least 18 months in the military as the country remains technically at war with its neighboring North.

Jaehyun, whose real name is Jeong Yun-o, debuted in 2016 as a member of NCT, whose over 20 members perform under various sub-units.

He launched a solo career in August with the album "J" and released a follow-up single, "Unconditional," in October.

WATCH: NCT's Jaehyun sings of deep devotion in 'Unconditional' MV

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