The AV Club as an interview with Susan Coyne, Bob Martin and Mark McKinney, the creators of Slings & Arrows whose first season was about a production of Hamlet:
AVC: Where did the Oliver [Stephen Ouimette’s character] come from? It’s rather unusual to have a ghost as a regular character.
BM: Well, not if the main thrust of your first season is a production of Hamlet.
MM: It was from talking about Hamlet, but a lot of Susan’s best ideas for the series she says and then goes, “Oh no, no, no. Too much, too much.” She came up with the ghost idea, which brought together about eleventy-hundred different things, in a really great way.
BM: The beauty of it, too, is that it wasn’t specifically a ghost. It’s really interesting to be having this discussion after you were discussing episode four [of season three] and seeing everyone wondering whether he was a ghost or just a manifestation of Geoffrey’s madness. He was always meant to be ambiguous. And remember when we had that conversation about should we have Bill Hutt see him, should we have Charles see Oliver, and how exciting that was?
My old review of Slings & Arrows is here. I really should return to it at some point.