The official Movie 19 Website has updated. Translations follow:

Pikachu Appears During the Special "Anime Kouhaku" Segment During the 66th NHK Kouhaku Utagassen



The Pokémon from the anime series "Pocket Monsters", spearheaded by Pikachu, will appear during the special "Anime Kouhaku" segment taking place during the 66th NHK Kouhaku Utagassen!
These popular, Japanese-born anime characters will gather on the Kouhaku stage for a special, one-night-only show!
The Pikachu will be there to cheer on the anime song contest between the singers participating in Kouhaku! Let's hype up the anime song contest!

This will be the first time "Anime Kouhaku" is held during the Kouhaku Utagassen. Wait and see what kind of wonderful stage show it will be!

Scheduled air time for "The 66th NHK Kouhaku Utagassen"
NHK General TV and NHK Radio 1, Thursday December 31st, 7:15pm to 11:45pm *with a newsbreak

For further information, see the Special 66th NHK Kouhaku Utagassen "Anime Kouhaku" Segment website

Source: http://www.pokemon-movie.jp/news/?p=1955