I just realized this! Secret Song Jieun, unable to deny when the MC asked Secret already have a boyfriend or not. Even her action (at 1:34) seemed to say that she already have one. Below are the link:

http://www.youtube.com/watch?v=MdZ4NYQTvz8

I hope they will annouced it soon. And I hope her boyfriend is Bang Yongguk. Ohh... my feelsss~~~~