old cast member returns to lost

Fans of 'Lost' know that this is the season where a lot of old favorites come back to the show, whether they're dead or not (well, mostly dead).

We've already seen Boone (Ian Somerhalder), Claire (Emilie de Ravin), Helen (Katey Segal), and Juliet (Elizabeth Mitchell - we assumed she died in the season finale last year but she popped up again for a teary goodbye with Sawyer). And now another well-loved character is coming back.

Who? Someone close to one of the characters above...