IU and Oh Yeon-jun set up a joint stage at You Hee-yeol's Sketchbook'.
In KBS2 You Hee-yeol's Sketchbook' on the 2nd day, IU and Oh Yeon-joon appeared singing 'Night Letter'.
The two, who appeared in the 400th special, caught the audience's ears with a pure tone.
You Hee-yeol asked the IU, "How about it when we're on stage together?"
"I was really surprised, I really liked it. I felt like this was the way it was, this talent was blessed and envious," the IU said.
About IU
Lee Ji-eun, also known by her stage name IU, is a South Korean singer-songwriter, record producer and actress. She signed with LOEN Entertainment in 2007 as a trainee and debuted as a singer at the age of fifteen with her first mini album Lost and Found.
 Wikipedia