World-famous K-pop boy group BTS congratulated fellow member's birthday together.

BTS member Rap Monster was born on September 12, 1994, turning 23 years old this year.
Fellow BTS members posted special messages to Rap Monster, along with their selfies taken together.
BTS' management agency Big Hit Entertainment also revealed never-before-seen pictures of Rap Monster to celebrate his birthday with his fans.

Meanwhile, '#HappyNamjoonDay' was trending on Twitter, as BTS fans worldwide wrote thousands of congratulatory messages for him.

Happy birthday, Rap Monster!

(Credit= 'BTS_twt' Twitter)

(SBS Star)