INFINITE's Sunggyu, who has been serving his compulsory military service since last May, surprised fans with a special letter expressing his gratitude for their support.

SEE ALSO: INFINITE's Sunggyu updates fans on his wellbeing after completing his basic military training!

The singer released the letter on September 10 through the group's official social media channels. The letter, which he handwrote himself, reads as follows:

"Inspirits! It's Sunggyu.

I am doing well. I received the letters you all sent me at boot camp, and I received strength from them, so I am writing a response.

Thank you so much for giving the live album I released during my military activities lots of love.

The 'Shinheung Military Academy' musical is ongoing, and thank you so much for giving me tons of support.

Thanks to all of you, I am gaining a lot of strength.

I will work hard during my time in the military, so don't worry and please take care of your health!

Don't forget me! Salute!

I'll be back!

- Private First Class Kim Sunggyu"