A week from Thursday, Grey's Anatomy fans will get to meet yet another of McDreamy's four sisters.

Derek’s previously unnamed sibling Lizzie, played by Neve Campbell, stops by Seattle. Take a look:

Lizzie makes her Grey's debut in the December 6 episode, "Love Turns You Upside Down."

It’s not known what promots Lizzie’s appearance in the Pacific Northwest, but the Shepherd family reunion comes as the surgeons face increased pressure to fix Derek’s injured hand so he may operate again.

Campbell's Lizzle is the third Shepherd sister we've met over the years, following Amelia (Caterina Scorsone, who went on to become a series regular on Private Practice) and Nancy (Embeth Davitz).

The fourth, Kathleen the psychiatrist, has yet to appear or be cast on the show; with any luck, we'll get to see her as well before Grey's takes its final bow, which hopefully isn't for several years.

What do you think brings Neve to town? Are you excited to meet her character? Discuss!

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.