Grey's Anatomy Has Cast Derek's Sister Kathleen Shepherd

The Gifted Amy Acker FOX

(Image credit: Ryan Green/FOX)

That was fast! It was recently revealed that Grey’s Anatomy would be introducing Derek Shepherd’s long-elusive and never-before-seen sister, Kathleen. Less than a week later, the medical drama has taken a huge step towards her debut. Grey’s Anatomy has cast Kathleen, and the role has gone to… Amy Acker!

The casting department just scored a major win. The Angel alum will be the actress to play Derek’s sister Kathleen “Kate” Shepherd, per TVLine. So, when can fans expect to finally see her? Amy Acker will make her debut in the upcoming Grey’s Anatomy episode focused on Amelia.

Unfortunately, that is the only episode of Grey’s Anatomy that Amy Acker is committed to starring in for now. That bittersweet portion of the casting news means that while viewers will finally get to see Kathleen, her appearance will be short-lived.

Amy Acker is currently starring in Fox’s sci-fi drama The Gifted. Depending on that series’ renewal status, Acker’s availability could theoretically change. The next step would be Grey’s Anatomy making room for Kathleen on a more permanent basis. For now, it seems like a short stint is in mind.

Grey’s Anatomy has cast an exceptional actress to play Kathleen, so they are not holding back. If she is a hit with the audience, it will make sense if Kathleen’s debut is not a one-and-done thing. As Derek’s fourth sister, she is the only Shepherd sibling to never before be shown on-screen.

To recap, Kathleen is a psychiatrist, who is married with children. The report does not mention if Kate’s spouse or her children will make an appearance alongside her. Given that is has taken 15 seasons to introduce her, it will be intriguing to learn what circumstances finally lead to her debut.

Amelia will undoubtedly be a factor. Considering that this episode is about Amelia, something major will likely go down for her sister to appear after all these years. While details on the exact plot of the installment are being kept under wraps by Grey’s Anatomy, one fact is known.

The episode will take viewers out of the hospital. Caterina Scorsone has said that the episode will be a “standalone” installment. What impact it will have on her overarching storyline on Grey’s Anatomy remains to be known.

Kathleen’s debut should solve a lot of mysteries. Talking about a character on a regular basis is one thing. Actually having them brought onto the show and getting a sense of them is another angle entirely. She has had a presence on Grey’s Anatomy without actually appearing in the flesh for a long time.

How she will match up with what Grey’s Anatomy fans have heard will be fun to find out. New episodes of new episodes of Grey’s Anatomy air Thursdays at 8 p.m. ET on ABC. The medical drama is among those airing new during the midseason.

Britt Lawrence

Like a contented Hallmark movie character, Britt happily lives in the same city she grew up in. Along with movies and television, she is passionate about competitive figure skating. She has been writing about entertainment for 5 years, and as you may suspect, still finds it as entertaining to do as when she began.