The remaining four members of K-pop supergroup BTS will begin their 18-month military service in South Korea this week, joining three others already serving, with fans pledging to wait until 2025 for them to perform as a group again.

A group of fans braved rainy weather on Monday to bid a temporary farewell to the seven-member band's leader, RM, and vocalist V in front of their boot camp in the central city of Nonsan.

"I think I'll be fine except for one thing, that I won't be able to make happy memories with you for a while, which is the hardest part," V wrote on fan platform Weverse on Monday, wishing fans well and happiness.