RM and V of K-pop sensation BTS began their mandatory military service Monday.

The two bandmates entered an Army training center in Nonsan, South Chungcheong Province together, according to industry sources.

V is reported to have volunteered to serve in the 35th Special Mission Battalion, a special duty team in charge of defending Seoul.

RM and V bid farewell to their fans through various posts on their personal social media accounts and the fan community platform, Weverse.

“The hardest part is not being able to make happy memories with Army (fandom name) for a while. I will come back healthier after 18 months so you should also take care of your health. Let’s make precious memories like we always used to when we come back,” wrote V on Weverse on Monday, posting numerous pictures of the group and himself with a short haircut.

He also asked his fans to enjoy various content the group has prepared for their fans to enjoy while they are away.

“The past 10 years that I’ve lived as BTS were filled with happiness. I do not doubt that something better will be waiting for us when this is all over. I believe that this time will serve to give us new inspiration and to learn,” RM also wrote to his fans on Weverse.

“I could be lonely once in a while but my heart will be filled with all your love. I hope that I can also fill your heart with my love. This is a farewell only for a while. Let’s meet in the future. I hope that my love reaches you all.”

Jimin and Jungkook will follow RM and V’s lead and begin their mandatory military service Tuesday.

With the four members enlisting this week, all seven members of the group will be actively serving their mandatory military duty.

Jin, the eldest of the group, began his service in December last year, followed by J-Hope in April and Suga in September this year.

Jin and J-Hope are currently serving as assistant instructors at a military recruit training center.

Suga is fulfilling his compulsory military service through alternative service.