On August 1, it was reported that Kiseop and Jung Yu-na are planning to get married on August 24.
According to the report, Kiseop and Jung Yu-na met when she featured in U-KISS' music video about five years ago.
At that time, Jung Yu-na was training under the same management agency as Kiseop.
It was explained that the two stars stayed friends for several years before they started dating each other.
Kiseop wrote, "Hi, everyone. I've decided to write this, because I've got something to tell you all. It may surprise some of you, but I'm getting married."
He added, "She is the most important person in my life and I believe I will never be able to meet anyone like her again. I want to make her happy for the rest of my life."
This March, Kiseop began his alternative military service as a public service worker.
Jung Yu-na is a newly-debuted actress who also works as a makeup model.
(Lee Narin, SBS Star)