Amelia's Sister Kathleen Is Coming To 'Grey's Anatomy' & Things Are About To Get So Complicated

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Derek Shepherd (R.I.P., he should have had a head CT) infamously had four sisters. Grey's Anatomy fans have met three of them over the course of 15 seasons — Nancy, Liz, and, of course, Amelia. But now Kathleen Shepherd is coming to Grey's Anatomy, and Amelia has already made this family reunion so awkward.

According to the preview for the April 11 episode (titled "Good Shepherd"), Amelia and Link took a trip to New York to operate on a spinal injury together. They were excited to have a little alone time, but then they accidentally bumped into Amelia's sister Nancy. On a whim, Amelia introduced Link as her husband. She then had to continue to the ruse through a family dinner that included both Nancy and the mysterious Kathleen.

Viewers know a little bit about Kathleen thanks to a few mentions throughout the seasons. TV Line reported that she goes by Kate and is a doctor of psychiatry. Entertainment Tonight reported that she's also married and has children. (Meredith even called her a good mother at one point.) Kathleen was also a potential candidate to donate a nerve to Derek back when he injured his hand in the plane crash. Liz ended up being the donor, though.

Besides that, though, viewers have been mostly left in the dark as to Derek's fourth sister. Until now. Kathleen will be played by actor Amy Acker (The Gifted, Alias, Angel), and the promo shows that she's jealous Amelia landed such a hot husband. (She doesn't know that Link is just pretending.) Amelia has always felt inferior to her sisters and brother, so it's not surprising that she faked having a husband to get her sisters off her back during a dinner. But it also doesn't look like the dinner goes all that well according to the promo pics.

Amelia Looks Like Someone Just Dissed Her

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She's biting her tongue to keep from saying something mean in return.

Kathleen Looks Like She's Saying, "What? I'm Just Being Honest!"

Mitch Haaseth/ABC

That's a face post-insult if I've ever seen one.

Link Looks Like He's Angrily Defending His Fake Wife

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Gotta love a guy who leans into a role.

More Than Once, No Less

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IDK what Amelia's family kept saying that upset Link this much, but, like, the Shepherd sisters need to chill.

Nancy Looks Concerned

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That is a serious disappointment glare.

And Kathleen Looks Like She's Making A Snide Toast

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Gurl, stop.

This Amelia-centric episode has been teased for a while, and Caterina Scorsone who plays Amelia was excited (but nervous) when she found out what went down. "I’ve been doing the show for a long time and just hearing what [the episode is] about fills me with nervous excitement," the actor told TV Line. "It’s not just, 'Let's follow Amelia to the neuro lab.' It’s definitely a little standalone. It’s almost like a little movie on its own."

A movie filled with a lot of awkward familial tension and a super big lie, it seems. Can't wait to see it all go down.