Celebs You Totally Forgot Guest-Starred on 'Grey's Anatomy'

William Daniels

Seasons: 8, 9
Mr. Feeny on Boy Meets World played a cardiothoracic surgeon who becomes Cristina Yang’s mentor.

Edward Herrmann

Season: 4
The late Gilmore Girls actor played an older surgical intern who is mistaken for a resident due to his age. He ends up moving from surgical to psychiatry.