Massive billboards of 2AM looking chic in all-black with the caption 'K-POP No.1 Vocal Group' can be seen on�tall buildings in major regions like Shibuya and Shinjuku of Tokyo.�These billboards were put up in an effort to promote the boys' new Japanese debut single "Never Let You Go" which is scheduled to be released in January 2012. Their Korean album 'Saint o'clock' released last September in Japan rose to the #3 slot on the Oricon charts, and therefore fans have high expectations for this debut single as well. Ahead of their Japanese promotions, the boys of 2AM will be also holding a Christmas concert on December 24th and 25th at the Jamsil Stadium in Seoul. Source & Image : OSEN via Naver