I agree with Malcontent, but i somehow don`t think that will be her avatar (or at least her whole one) maybe it will be just a new resserectionist model. My bet (okay it is just a wish) is that her Ghost will be her avatar (also possibly alongside her body).
If not i will be really annoyed Lady J is and was my favorite Master and i really don't like zombies.
The only thing we can be sure of, thanks to the tweet, is that she is dead, but i will be crossing my fingers for a non zombie avatar.