John Lithgow Sheds Lights on Arthur Mitchell, Dexter Season Finale

Attention all other supporting actors in a drama: don't bother submitting your name for the Emmy Awards next year. John Lithgow has the category locked up.

The actor has mesmerized and frightened Dexter viewers throughout season four, culminating in the closing scene of this week's episode, where Arthur confronted Dexter at work and confirmed the latter's worst fears:

The Trinity Killer knows his identity.

Lithgow spoke with CBS' Harry Smith this week, explaining how he got the role on Dexter and offering up the tiniest clue about Sunday's season finale. (Warning: the video begins with a clip from it.)

For a full clip from the season four finale, follow this article's jump - and remember to return to TV Fanatic soon after it concludes for a detailed recap and review of the shocking events!