When the second season of 'Slings & Arrows' opened, it was the last day of performance for the New Burbage production of "Hamlet". Rachel MacAdams and Luke Kirby returned for just the one episode to bring a close to their sweet love story as stars of the play Kate McNab and Jack Crewes.
However, it wasn't a seamless transition from one season to the next when it came to the actors and the characters they played. When "Hamlet" opened in the final episode of the first season, the role of Claudius was played by a tall, lanky, somewhat big-eared actor who might one day be considered for playing the role of Abraham Lincoln.
But with Season Two, we saw that Claudius was being played by Brian Cabot (as portrayed by Leon Pownall). Brian was shorter and quite rotund, with a small white beard and a manner of dress that seemed to suggest to me that he grew up near the sea. (Hence, I'm thinking that he may somehow be related to the town founders of Cabot Cove, Maine, as seen in 'Murder, She Wrote'!)
This is a "Re-Castaway" case in which we can actually cite re-casting as the reason behind the change in characters. Such a reason can't be used in most cases as that's a behind-the-scenes decision made in the Real World and thus can't be considered within the inner reality of Toobworld. But this time it works, mate!
For reasons unknown, the actor originally hired to play the role of Claudius must have dropped out of the production. Perhaps he got a role in a TV series to be filmed in Toronto, or headed west to Vancouver to film a role in a movie that was supposed to look like New York City.
Brian Cabot was a long-standing member (up to that time) of the troupe at the New Burbage Shakespeare Festival; his association with the late Oliver Welles, who used to be the festival's artistic director, went back many years. We know from the very first episode of Season One that there were certain actors in the company for whom there were no roles that season and so as a thank you for past contributions they were given complimentary ducats to opening night of "Midsummer's Night's Dream". Perhaps Brian Cabot was one of those actors.
Or more likely, since he did have the perfect bearing for playing Claudius, it could be that he was not available at the time of casting and rehearsal for "Hamlet" to play the murderous King. (Ooh! Is that a spoiler?)
Mayhaps he was the one who was busy in Toronto or Vancouver filming some other production. (If the character's life mirrored that of the actor, that's likely - it seems from the IMDb.com, that Leon Pownall has been quite in demand for his services on both sides of the border.)
So that's the easy way out splainin for the two different characters portraying Claudius from one season to the next. And I must say it's nice to be able to come up with a reason that doesn't depend on plastic surgery, alien/android impersonations, or quantum leaping!