A new doctor is coming to Seattle Grace!Entourage and Boston Legal alum will play Dr. Cahill, a confident, self-possessed and laser-focused doc with a wicked sense of humor. Details of her specialty are being kept under wraps, but we'd like to think she could be another surgical fellow who keeps the attendings on their toes. Or maybe she's a new love interest for Owen (Kevin McKidd). Yeah, we said it. Who do you think she'll tangle with? Zimmer's casting follows that of Nip/Tuck alum Roma Maffia, who will play a Seattle Grace board member in a potentially recurring role.Royal Pains, Pushing Daisies and the upcoming Netflix series House of Cards, will first appear in an episode slated for late January.Grey's Anatomy airs Thursdays at 9/8c on ABC.