Both Wheesung and Fly to the Sky were guest stars on SBS radio program 'Cultwo Show' on May 29, where they revealed that their history actually went way back before the show.

The DJs said, "Hwanhee and Brian both appeared on the radio before, but separately; it has really been a long time since Fly to the Sky came here."

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The three guests revealed they have been close friends for a while, stating that Brian was one year older while Hwanhee and Wheesung were the same age.  

In addition, Wheesung revealed, "I met Hwanhee in my third year of high school at an occupational school for music. At the time, Hwanhee was preparing for Fly to the Sky while I had tried something and failed. I knew Hwanhee would succeed." 

Both of them ended up succeeding! A Wheesung and Fly to the Sky collaboration would be amazing, don't you think?