It happens at least five or six times per year: Actor X, currently a regular on TV Show A, gets cast in TV Show B and fans of TV Show A freak out, because they know this means that Actor X's character is on the verge of dropping down an elevator shaft, getting attacked by bees or having a full episode dedicated to their "wedding."

You want to yell at Actor X's publicists and representation, "Yes, we know you want word to get out that your client is alive and working, but why must you ruin TV for your publicity needs?"

I guess the other alternative is that Actor X's casting in TV Show B means that TV Show A is about to be cancelled and Actor X is just a rat fleeing the sinking ship because, once again, actors like to work and are encouraged to seek steady paychecks.

That was a preamble to today's casting news that "House of Cards" Golden Globe nominee Corey Stoll is joining the fourth season of Showtime's "Homeland," which led to several confused or perplexed or concerned tweets regarding Stoll's future on FX's "The Strain," which hasn't even premiered yet. 

Bottom Line: It means nothing. Don't worry. Move on. "The Strain" premieres on FX on July 13. The first season is in the can. The second season hasn't been ordered yet -- Barring the sort of bizarrely low ratings I can't even imagine, it will certainly be renewed -- and it wouldn't begin production for a few months, by which time Stoll's guest-starring role on "Homeland" would be in the can. And if you know Guillermo de Toro and Chuck Hogan's "Strain" trilogy of novels, you know that at least for the immediate future, Stoll's Ephraim Goodweather is the main character.

So nothing about the first season of "The Strain" has been spoiled by Stoll's "Homeland" casting. Of course, I guess that I've spoiled some of it here?

Sigh. 

Per Showtime, Stoll will play Sandy Bachman, CIA Chief of Station in Pakistan, described as "a rising star in the Agency's firmament."

Adding to suspicions that the fourth "Homeland" season will involve Pakistan is the announcement that Laila Robins ("Bored to Death") will be a regular this season playing Martha Boyd, Ambassador to Pakistan.

Regarding the season, Showtime teases, "Season four will find Carrie assigned to one of the most volatile and dangerous CIA stations in the Middle East where she is back on the front lines in the war on terror."

Fair enough.

The fourth season of "Homeland" begins production in Cape Town, South Africa later this month and will premiere on Showtime this fall.