It's Elizabeth Reaser!
The two actresses, both 39, attended Juilliard in the late '90s, overlapping by two years.
Longtime Grey's fans will remember Elizabeth as Rebecca/Ava — the patient with whom Alex (Justin Chambers) fell in love before she started having psychological problems — but she has also appeared in The Good Wife, Bonnie and Clyde, and a little franchise called Twilight.
A Twitter fan asked Elizabeth if it was true that she has known Sara since college, way before the days of Grey's Anatomy. "Yes, she was the baddest," Elizabeth replied. "Third-year when I was a first-year — intimidating amount of talent!"
Sara retweeted the answer, adding, "Back at ya! XO!"
Sure enough, Sara attended the New York City-based school as a member of Group 26 — along with Suburgatory's Alan Tudyk and Parenthood's David Denman. Two years later, Elizabeth joined Group 28, which also included John Carter's Lynn Collins and Orange Is The New Black's Michael Chernus.
That's all well and good, but why haven't our classmates achieved worldwide fame? Slackers, all of 'em!