On the most recent episode of the MBC entertainment program 'Infinite Challenge,' which aired on December 27, 2014, singer Kim Sung Soo of the popular 1990s group 'Cool' said that he wants to be a regular member of 'Infinite Challenge' again.

On this day's episode called 'Saturday Saturday Is a Singer,' a number of 1990s singers got up on stage and sang their songs which were popular back in the 1990s. Bada and Shoo of S. E. S., a popular girl group of the 1990s, performed with Girls' Generation's Suh Hyun. Singer Kim Sung Soo met with the Infinite Challenge members and talked about how he used to be a member back in the days. He said that he regrets leaving Infinite Challenge a lot, and asked Yoo Jae Suk if he had any chance. Yoo Jae Suk said "Unlikely," and made people laugh. In related news, on the most recent episode of the popular MBC entertainment program 'Infinite Challenge,' the members recruited popular singers from the 1990s and hosted a stage performance, showing popular songs from the 1990s. The MBC entertainment program 'Infinite Challenge' is one of the popular, long lasting entertainment programs in Korea. It features the Infinite Challenge members Ha Ha, Park Myung Soo, Yoo Jae Suk, Jung Joon Ha, and Jung Hyung Don.