As long as she's on top of her own lines and takes direction, I couldn't care less what books she reads.
I think a bigger danger may be those who know the ultimate fate of their characters. (Not just whether they live or die, but how more or less sympathetic they may become as ASoIaF progresses.) If their character is (un)sympathetic in AGoT, the book, it ought to be so in season one of AGoT, the TV series, whatever happens in ACoK, ASoS and AFFC, the books.
Good actors, scriptwriters and directors should all do their best to bring AGoT to the screen and then do the same for the other books.
I think a bigger danger may be those who know the ultimate fate of their characters. (Not just whether they live or die, but how more or less sympathetic they may become as ASoIaF progresses.) If their character is (un)sympathetic in AGoT, the book, it ought to be so in season one of AGoT, the TV series, whatever happens in ACoK, ASoS and AFFC, the books.
Good actors, scriptwriters and directors should all do their best to bring AGoT to the screen and then do the same for the other books.