Amy Acker

The fourth Shepard sister has been cast on Grey’s Anatomy. Amy Acker, who currently stars on Fox’s “The Gifted,” will play Kathleen Shepherd, the last of Derek Shepherd’s (Patrick Dempsey) siblings, People magazine has confirmed.

The 42-year-old actress, best known for starring as Winifred Burkle and Illyria on the supernatural drama series “Angel,” will appear in the Amelia-centric episode, which is slated to air later this season.