We now who who will play the role of Derek Shepherd's never-before-seen sister Kathleen.
Acker has previously appeared in television shows including The Gifted, Person of Interest and Angel.
She joins actresses Embeth Davitz and Neve Campbell who have played Derek's other sisters Nancy and Liz respectively.
This story was originally published February 8.
Derek might be dead, but Grey’s Anatomy is proving he is certainly not forgotten. First, showrunner Krista Vernoff chose to add an episode focused on Amelia, Derek’s youngest sister, this season — she first appeared on spinoff Private Practice and has been a series cast regular on Grey’s since season 11. Now, the long running medical drama is poised to introduce Derek’s never-before-seen sister Kathleen in an upcoming episode.
TV Line reports the thus far MIA Kathleen will appear in the Amelia-centric hour that is set to air this spring. Though we don't yet know who will play the mysterious Kathleen, we do know Michelle Forbes is set to guest star in an upcoming episode. And that Hailey Bieber recently expressed interest in making a cameo, but she may be a little too young to pass for a Shepherd sister. (Quick refresher: Dr. Derek Shepherd has a whopping four sisters: Nancy, Liz, Amelia, and Kathleen.)
Though we have yet to meet Kathleen, it’s clear Meredith has. In season nine, when Meredith and Derek are updating their will to choose guardians for their kids should anything happen to them, Meredith tells Cristina that Kathleen “seems like a good mom” and her “kids seems sane.” This should count as glowing commentary from the often judgmental Meredith. (And further proof that Baldwin probably won’t be playing this particular characters.)
We’ve been told that Kathleen is a trained psychiatrist. From everything we’ve heard about her, she appears to be somewhat of a leader of the Shepherd sister circle, eager to give directions to Nancy (whom we met in season three) and Liz (whom we met in season nine). That said we’ve never seen the sisters interact and with the new episode set to revolve around Amelia that is almost a sure thing. It’s unclear if we’ll see Meredith interact with the elusive Kathleen but considering both women sound like forces to be reckoned with it would be a disservice to fans if we didn’t.
It was recently revealed that Meredith’s dad was at Derek’s funeral and it’s safe to assume his sisters and his mom (previously played by Tyne Daly) were there too, yet we’ve heard little about them since his death. When Liz donated her nerve to Derek in season nine, Meredith had promised to try and have a closer relationship with Derek’s sisters, but it appears that with the exception of Amelia that never really came to pass. We know that Amelia and Derek’s relationship was at times chilly but they shared as special bond given they were both present when Derek's father was shot to death.
Though viewers know the depth of the trauma Amelia has experienced (drug addiction, the loss of a baby and a brain tumor in addition to the loss of her father and brother) it’s unclear whether her sisters know all of this. Given that Amelia appears to be diving head first back into her relationship with Owen (who is about to have a baby with another woman), is mentoring a teenage girl struggling with drug addiction and also ya know trying to save lives, she certainly has plenty to talk about with her sister in the upcoming episode.
It seems like the Shepard family is a little secretive but if we know anything about Grey’s at this point it’s that the show knows how to tug at your heartstrings and secrets never stay secret forever.