ew spoilers

Question: Is Elizabeth Mitchell leaving Lost? It will break my heart if she does. --Cristiane
Ausiello: I address the murky Mitchell situation in this week's EW (on sale Friday), but this much I can tell you now: Juliet will definitely appear on Lost next season.

Question: Please give us a hint about the big death in the Lost finale. Bill
Ausiello: Just this one: That's not what people will be talking about the next morning. Trust me.

source : ew