On December 29th, B2ST's Yoseob had a wonderful duet performance with IU at the 2011 SBS Gayo Daejun. On January 2nd, SBS E! K-Star News aired a special featuring some backstage footage from the Gayo Daejun and it seems Yoseob was quite nervous for the performance. Before the performance, he had a short interview session with a reporter:

Yoseob: I'm singing a song with IU sunbaenim. Reporter: What song is it? Yoseob: "If you want a lover." Reporter: If you were really to have a girlfriend what would you do with her? Yoseob: Go to the amusement park and have a surprising event as well. Reporter: If you were to date IU? Yoseob: I'm so nervous and shy, how can that happen? I can barely even sing with her.

After the performance, both IU and Yoseob were asked how the performance went. While IU seemed perfectly fine answering, "It was fun," Yoseob on the other replied, "I was shaking... I really was shaking... Ah, I feel so shy." Check out their wonderful duet performance below! Tip: Madison