"Mnet's M! Countdown" returns on December 23rd with another weekly fun-filled music show, and this episode was packed with awesome performances as usual. B2ST members were special MCs for this Happy MCD-Mmas episode! For today's show, GD&TOP made their much anticipated debut, with the most expensive stage ever constructed in Mnet's history. Elsewhere, IU had a Christmas stage performance, while the B2ST members split up into three units of two and made their duet debut as well! MCD Awards nominated idol boys and girls separately for Best Eve Boy and Girl? T-ara, Yang Dong Geun, Seo In Young, Park Hyo Shin and Younha say Merry Christmas. Meanwhile, it was a battle between IU and T-ara for the #1 spot on M! Countdown today, and in the end, it was IU who came out on top as she ends T-ara's run of two consecutive wins plus nabbing her first solo win on the show! Congratulations to IU! Other performers include F.Cuz, Tim, Bohemian, Bebe Mignon, Mtifulday, Jo Moon Geun, and Seo In Young. Jo Moon Geun Bebe Mignon Seo In Young Mtiful Day Tim F.Cuz - Midnight Sun Bohemian