Q: Context: Kathleen Erin Walsh (born October 13, 1967) is an American actress and businesswoman. Her roles include Dr. Addison Montgomery on the ABC television dramas Grey's Anatomy and Private Practice, Rebecca Wright on the short-lived NBC sitcom Bad Judge, and Olivia Baker on the Netflix drama series 13 Reasons Why.

Question: who plays addison montgomery on grey's anatomy?
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To answer this question, we should know that: Her roles include Dr. Addison Montgomery on the ABC television dramas Grey's Anatomy and Private Practice, Rebecca Wright on the short-lived NBC sitcom Bad Judge, and Olivia Baker on the Netflix drama series 13 Reasons Why. So the answer is Kathleen Erin Walsh.