BTOB’s Changsub starts military service

Lee Chang-sub, a member of the seven-piece K-pop boy band BTOB, started his 21-month mandatory military service Monday, temporarily leaving the band.

The 28-year-old uploaded a photo of himself in military cropped hair on his personal Instagram account (@lee_cs_btob) early Monday afternoon, when he was enlisted.

“I will be back,” he said on the account, adding the four-syllable abbreviation for “I love you now and in the future as I did in the past.”

He will undertake rudimentary training at the military boot camp before officially joining the armed forces.

“As he wants it to be a quiet event, the timing and the location will not be disclosed,” the group’s management agency, Cube Entertainment, said.

He debuted in 2012 as the main vocalist of BTOB and later extended his career into musicals.

Last month, he released his first solo album, “Mark,” and threw his first solo concert.