Singer Lee Juck praised IU that he was amazed by her unusual talent. On December 7, Lee Juck posted on his homepage (LeeJuck.com) board about his assistance with the song 'Uncle', from IU's 2nd album. Lee Juck wrote, "Last week I worked with IU on 'Uncle', wasn't it the cutest song?^^", then he revealed that it was a song he thought up as soon as he received the request. Lee Juk explained, "In order to figure out an idea for the lyrics, I wanted to learn more about IU, so I met up with her to talk. While talking about this and that, I saw that her thoughts were much deeper than I first thought and she also had a dark corner and many worries. I thought she would just be enjoying her current stardom without a care, but in fact she had a very discerning eye and objective view of her current situation." Lee Juck praised IU for her maturity in this way. He continued, "For an hour, we sat in front of the keyboard and computer and excitedly wrote the lyrics to 'Uncle'. While she talked on and on, I worked on taking down her words and rearranging them into lyrics. On 'Infinity Challenge' I turned Jae-suk's story into lyrics, but this was a completely different model of a joint creation." Lee Juck did not hold back from giving praise, saying, "It was a time where I was amazed by IU's unusual talent (storytelling and vocals). Lee Juck then added comments about his concert 'Enemy's Counterattack'. He explained, "I am diligently preparing to start a new chapter that involves not just musical, but visual, elements. It'll be a two-day concert, but using a 2-day cue sheet is a bit new to me." Lee Juck announced, "I will be performing with various artists. It will be people I've collaborated with this year, Dynamic Duo on Dec 17, and on the 18th we will go crazy with MC Nal-Yoo (Yoo Jae-suk)." Lee Juck finished off his comment by posting, "Just as IU's 'Uncle' is fiction, I am not called IU's uncle, but 'elder brother'."