Seunghyun has recently left his label and group F.T. Island to start a new career as an actor. 

Seunghyun uploaded a letter to his personal Instagram on December 24:  

"Hello, this is Seunghyun. First of all, I'd like to apologize for shocking all of our Primadonna fans.

Starting with a Japanese single "I Believe IN MYSELF" and 2009's Korean schedules through F.T. Island,I was able to join as a new member and spent a total of 10 years of time with the group receiving love. 

I was so glad I got to share my love with you. Without even knowing, 10 years have passed on. I took a long time to make this decision with a hurting heart and lots of pondering. I participated in conversations with the members and made this hard decision. To be honest, my hands are trembling because I don't know what else to say. I want to apologize again to my fans for having to deliver this news. 

Since I entered the F.T. Island team, I will have memories I will never forget. To me, I felt burdened and worried that I wouldn't be able to catch up with my team of sunbaes when I started. I am very lacking and still very naive but I think I was able to potential due to the care and love I was given by the members. I didn't want to hurt the team and wanted them to shine a little more. I think this was my driving force as I continued being in the band. 

Recently, many things happened to our team. Sad things. Happy things. Living life, we experience a number of different emotions and I experienced many of them. Until now, I can end my performance on stage. For those fans who have been waiting for me, thank you for being a strength to me unconditionally allowing me to rise to the top. The heaviness in my hear turned to nervousness and started eating away at me. I got to look back at myself, lonely and suffering and thought about myself. I've been a member or a long time and this is a decision that was made very heavily after much discussion with the label. I know there are fans who will be disappointed in me and that scares.. and the thing I'm most sorry about... I changed a lot of what I had said in the past. 

However, this time I will bring about a little courage and look back at the Song Seung Hyun that I was. I want to achieve my career goals but also want to look at myself, the places I hurt, and heal, a decision I made after a long time. 

I was so happy. Thank you so much. I will miss you a lot. And I am so very sorry. While I was in F.T. Island, I dreamed dreams that no one could have possibly have even thought of. I'm glad I got to dream those dreams with you. 

Now I'm planning on trying my best once again. F.T. Island's last album was not able to make it to my list but my heart is with hem and I hope they shine and stay well and healthy to become more mature artists. 

Thank you for reading this long letter. Again, I was happy as a guitarist in F.T. Island. 

Lastly, Hongki, Minhwan, Jaejin, and the faraway leader hyung... we did really well! We won through it. From now on I hope you become a brighter team and I thank you for the memories. 

And thank you to Han Sung Ho CEO for letting me a part of the team in the first place. And our FNC staff members, thank you so much for your hard work.

Thank you."