GRRM’s having fun by releasing more hints about the casting. He does indicate most people have figured out one of the clues, indicating two of the roles belong to the children; he further adds that those actors are not listed in IMDB although a number of individuals in there share their name. He also states that casting continues, now aimed for actors to fill smaller roles.
The hints are as follows:
“In the absence of an announcement, I’ll give you a few more clues. One cast member was played by a puppet. Another has been seen wandering a castle exclaiming about roses. A third is too good to be true. The fourth is the fifth. Esquire thinks one of them is hot.”