Lee Hyori appeared as a guest on the Infinity Challenge special called Infinity Challenge Crime and Gil as a witness against Yoo Jae Suk. The episode, which took place in a court settings, was about Gil suing Yoo Jae Suk for defamation of character. The whole issue started when Yoo Jae Suk revealed in an earlier episode that Gil peed on public property last summer. Gil, Park Myung Soo and Jung Junha said, "This is clear defamation of character." On the other hand, Yoo Jae Suk, Jung Hyun Don and Noh Hong Chul said, "We only revealed the truth. It's actually a good thing if we build a character for someone in variety shows." Now, a trial is not complete without a line of witnesses. This trial included an impressive list of witnesses ranging from Lee Hyori, Gil's stylist, PDs and more! Lee Hyori, especially, heated up the court room with her fiery comments attacking Yoo Jae Suk. She said, "He is called the nation's MC Yoo Jae Suk, but in real life, he doesn't always speak the truth." Lee Hyori and Yoo Jae Suk have been in the entertainment business and known each other for nearly ten years, so she had lots of things to say about her buddy. When Lee Hyori and Yoo Jae Suk won the Entertainment Award last year, on air, Yoo Jae Suk said, "The reason the program was successful was Lee Hyori." However, in a phone call with a friend, Yoo Jae Suk said, "Well, I didn't even receive the award alone..." in a very disappointed manner. And that's not it! She revealed that at the after party of MBC Entertainment Award last year, he said, "Winners and loser should sit separately." Yoo Jae Suk replied, "I was just joking," however, the court room was already heated up with the rivalry between Lee Hyori and Yoo Jae Suk. Lee Hyori did not stop there. She continued to say things only a best friend could say, like, "Honestly, I am tired of Yoo Jae Suk's comedy. He's been doing the same thing for ten years." Hurt by her betrayal, Yoo Jae Suk said, "But you continued to work with me in a program for one year and eight months because you had confidence in me. Didn't you?" Lee Hyori replied calmly, "I only did it because I was signed up for it," which made the entire court room burst out in laughter. This episode was full of laughter, rivalry and quarrels among the Infinity Challenge members and friends! So, who is guilty? Watch the episode to find out!