We've already had news regarding new additions to the Hyrule Warriors roster, and tomorrow Japanese video sharing site Niconico will be live streaming footage of the game — presumably showing these fresh combatants in action.
The event will take place at 9PM Japanese time, which is 1PM if you're based in the UK. For North American readers, it's 8AM Eastern, 5AM Pacific.
Point your browser at this page at those times tomorrow to watch and learn.
Hyrule Warriors launches in Japan on August 14th, with the North American and European releases happening on 26th and 19th of September respectively. In the meantime, feel free to tide yourself over by watching the off-screen footage we captured at Nintendo UK's recent post-E3 event in London.