Usually at most boards they allow you to make signatures for your characters, using a celebrity of some sort to give their characters a face. This is exactly the same here. In order to make sure someone doesn't use the same person for their character signatures, here is a list of people who are taken already:

Alicia Witt - Elizabeth Tudor - Ana
Anne Hathoway - reserved for Lady Jane Grey - Tabby
Hugh Dancy - Robert Dudley - Kyle
Scarlet Johansson - Reserved for Elie

If you want to reserve a face please PM me or post on the GD discussion forum.