MBC's Music Core has returned once again with another fun and exciting show! On today's show, Seo In Young, T-ara, Younha, and IU had their comeback stages, while After School returned with a Christmas stage for charity. MC Cuts for today's episode. Other performers for the December 11th episode include�KARA, S.M. The Ballad, 2AM, Gavy NJ, SISTAR, December, Brian, Lisa, Lee In Se, Untouchable, OP.one, JJ, and Soul Harmony. Check out all their great performances below! Also check out KARA, SNSD, Kim Jang Hoon and PSY's One Love concert message.