It depends on the canon. If it's a movie that has been recently released, there is no waiting period, just warn for spoilers appropriately. If it's an ongoing series that only has one episode/chapter out, we might want you to wait (but again, it depends on the canon. A children's show is less likely to have plot twists than something by Joss Whedon, so we'd be more lenient with it).

However, as the the opening date isn't for a few weeks, we feel it's safe to reserve the character.