Amy Acker, who currently stars on Fox's The Gifted, will appear as Kathleen Shepherd

By Christina Dugan
February 13, 2019 03:03 PM

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 has confirmed. The 42-year-old actress will appear in the Amelia-centric episode, which is slated to air later this season.

Throughout the past 15 seasons, fans have been introduced to the late doctor’s three sisters — Liz (Neve Campbell), Nancy (Embeth Davidtz) and, of course, Amelia (Caterina Scorsone) — but have never had the pleasure of meeting the infamous fourth.

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Two weeks ago, Meredith Grey’s (Ellen Pompeo) father, Thatcher Grey (Jeff Perry), made his final guest appearance in an emotional episode.

In an exclusive chat with PEOPLE following his character’s death, the actor spoke about his experience back on the Grey’s set.

“Actors are weird creatures. Unlike more sane humans, we seem to enjoy going into the territory that is shaky and most vulnerable,” the Scandal alum told PEOPLE of what it was like returning for his final scenes. “So, I was really excited by the thought to get to the unresolved.”

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“Meredith’s final response to me and speaking with such love in my last moments, describing her motherly love, was beautiful,” said Perry, 63. “I thought it was sentimental in the best way. Never a perfect closure, we humans never do that, but it was the best they authentically could have come up with.”

He also admitted that dipping back into Shondaland after starring on Scandal was “great and deeply comfortably.”

Grey’s Anatomy airs Thursdays (8 p.m. ET) on ABC.