Addison Adrianne Forbes Montgomery, M.D., F.A.C.S., F.A.C.O.G.,[1] previously known as Shepherd, is a fictional character who first appeared as a supporting main character on the ABC television series Grey's Anatomy, and as the protagonist of its spin-off Private Practice played by Kate Walsh. Addison is a world-class neonatal surgeon[2] with board certifications in both obstetrics and gynaecology and maternal–fetal medicine.[3] In addition, she has completed a medical genetics fellowship.[3][4]