On the September 8 broadcast of KBS2's 'The Seasons - AKMU's Last Goodbye', H1-KEY reunited on stage with DAY6's Young K, the lyricist of H1-KEY's hit song "Rose Blossom". 

Young K, who was also appearing as a guest on the music program in light of the release of his 1st full solo album 'Letters With Notes', delivered a riveting performance of his title track, "Nothing But". 

The musician then sat down for a chat with hosts AKMU, opening up about his experiences while carrying out his mandatory military service in the KATUSA as the first ever K-Pop idol to do so. He revealed, "I met so many different kinds of people. People that I would never have met otherwise. Including many American soldiers. It was a novel and fun experience." Young K then sang a cadence sung by the KATUSA soldiers and the soldiers of the United States 8th Army, impressing the audience. 

Next, it was noted that Young K actually wrote the lyrics for a hit song during his military service, H1-KEY's "Rose Blossom". Here, the four members of H1-KEY joined Young K on stage and surprised the audience. In particular, member Riina confessed that she was a big fan of DAY6, and was amazed when she found out that Young K had written the lyrics for their song. 

In fact, the members of H1-KEY chose to express their gratitude toward Young K for working on their songs on this day, by singing a cover of DAY6's "You Were Beautiful" (below). 

Finally, H1-KEY and Young K took to the stage to perform "Rose Blossom" together, showcasing their chemistry! 

You can check out more clips from this week's broadcast of 'AKMU's Last Goodbye' with guests Young K and H1-KEY, including H1-KEY's performance of their comeback track "Seoul (Such a Beautiful City)", above and below!