You know that male-nurse role that ER is currently casting as a love interest for Linda Cardellini? I just heard that one of the finalists used to be on that little vampire show that Joss Whedon did a few years back. And this particular actor was not a mere guest star; he was a series regular. Name and face in the opening credits and all. He's up against some stiff competition for the plum ER part though, including a (Easter egg alert!) popular acting titan. A winner is expected to emerge by week's end. As soon as I know, you'll know (give or take a few seconds).
(Disclosure: TV Guide is owned by CBS Interactive, a division of ViacomCBS.)