Grey's Anatomy Poised to (Finally) Introduce Derek's Elusive Fourth Sister

Grey’s Anatomy‘s forthcoming Amelia-centric episode has officially morphed into a full-fledged event. TVLine has learned exclusively that the Caterina Scorsone-driven hour will at long last introduce late Derek Shepherd’s oft-mentioned-but-never-seen fourth sister, Kathleen. An ABC spokesperson confirmed that casting for the pivotal role is underway, but the rep declined to provide further details. Little is known about the […]