Cote de Pablo returning to NCIS for the season premiere!

Surprising absolutely no one since there was no body and she "died" off-screen, Ziva isn't actually dead - they planted hints throughout this season - and she showed up to shock the hell out of Gibbs at the end of tonight's season finale. It's been confirmed that she will return for the season premiere. They filmed Cote's return so secretly that no one was told and they filmed the scene only in the dead of night with a skeleton crew.

Sources 1 and 2