Dissidia 012: Duodecim is set to be released quite soon; March 3 in Japan, March 22 in North America, and March 25 in Europe. In recognition, Squenix is holding a launch event - and it will be streamed on the internet. I hope you speak Japanese, though, because it will be in Japanese and the site it's being streamed on is NicoNico Live - a Japanese video site. You'll need to make an account on NNL if you want to watch it, so, again, I hope you speak Japanese.
The event is to release information about the game, show how the competitions will work, and star some "special guests". Whether or not they'll be announcing new characters or just giving information on ones they've already announced remains to be seen.
Actually, I've never played Dissidia. To me, Final Fantasy is an RPG series, not a fighting game series, and I don't do fighting games too much. But I know a lot of people like it, and it is always exciting when anything new that's Final Fantasy-related is released.
Source:
Final Fantasy Union