SEE ALSO: Lee Da Eun reveals text messages with late Kang Ji Yong's mother following family dispute

He wrote,

My lovely ToppKlass,

I'm sorry that the first news I bring in a while is of me leaving... You guys are doing well, right? I'm really sorry and disappointed myself that even though you showed me love I didn't deserve, I chose to enlist in the army instead of standing no the comeback stage. However, I'll work harder and grow more even after I enlist so I can comeback with more mature music than right now. 

Please show a lot of love to Topp Dogg's album that's going to be released soon! I really think its packed full of good music!

Also.. my lovely members! I'm so thankful and also so sorry. I'm cheering you on!

All the fans who loved Gohn, I love you so much. Thank you.

P.S. CEO, I was really thankful. I'll be back soon.

P.S. P-Goon hyung, happy birthday!! I can't believe I'm going before you... ?

Best of luck to Gohn!