TNT's blockbuster post-apocalyptic drama series "The Last Ship" just added two new additions to the cast for Season 3 of their hit series.

According to Deadline, former "Law & Order" actress Elisabeth Rohm has joined the cast for the show's third season moving forward. She will be portraying the role of Allison Shaw, who is the Chief of Staff to President Michener (Mark Moses).

Shaw is a highly intelligent woman who serves the new president with incredible authority as she navigates the turbulent new world that has been ravaged by disease and politics.

Rohm has been listed as recurring throughout Season 3, but that could change.

On the main cast side, "Jane the Virgin" alum Bridget Regan has been added for a complete run during Season 3. Regan will be portraying a woman named Sasha, who was a former Navy intelligence officer.

Sasha will be operating under diplomatic cover in China for the newly reformed U.S. government. It is unclear at this time if she will play a friend or foe to the U.S.S. Nathan James.

The series, which hails from executive producer Michael Bay, has been a hit with viewers on the cable network. It all started out when a plague hit the world and wiped out nearly the whole global population. The crew of the U.S.S. Nathan James were mostly protected from the plague, given they were on assignment at sea. This kept them quarantined away from the deadly disease, but once the crisis died down, they were charged with finding survivors and in some way, healing or rebuilding the world.

Of course that led to major conflicts on the home front when politics came into play and the people who were immune to the plague ended up rising to assume power.

There has been no word yet as to when Season 3 will premiere, but it is a summer series and will likely come in June or July.