The cast of Grey's Anatomy [1] just keeps getting bigger! After the exciting introduction of Dr. Atticus "Link" Lincoln [2] and Dr. Nico Kim [3], the long-running medical drama is now bringing on another character: Kathleen "Kate" Shepherd.

Before you ask, yes — she's a member of that Shepherd family. EW confirmed [4] on Friday that Grey's Anatomy [5] is currently on the hunt for an actress to play Kathleen, who is the fourth sister of the late Derek Shepherd (Patrick Dempsey [6]). Her existence was first mentioned way back in season three, and since then, we've met the other members of the Shepherd clan: Amelia (Caterina Scorsone) [7], Liz (Neve Campbell), and Nancy (Embeth Davidtz). Like the rest of her family, Kathleen is also a doctor (she's a psychiatrist, to be specific).

Sadly, there aren't that many other details about the new character just yet, but hopefully more information about her — and why she's visiting Seattle — will start rolling in once ABC casts an actress to play her.