Supernatural goes meta (again) in the Feb. 25 episode. Here's the official description for the show, which is titled "The French Mistake."
I liked it when Growing Pains did a similar episode, so maybe I'll like this too. Let's just hope they don't take it too far.
SAM AND DEAN ARE TRANSPORTED TO AN ALTERNATE REALITY — Raphael (guest star Lanette Ware) launches an attack on Castiel (Misha Collins) and his allies, sending a particularly frightening angelic hitman (guest star Carlos Sanz) after Balthazar (guest star Sebastian Roche), Sam (Jared Padalecki) and Dean (Jensen Ackles). In an effort to protect the brothers, Balthazar sends them to an alternate universe where they are the stars of a TV show called “Supernatural” and they are actors named “Jensen Ackles” and “Jared Padalecki.” The brothers are confused when Castiel appears to be a tweet-happy actor named Misha Collins and Sam is married to Ruby (Genevieve Cortese). Posted on KSiteTV. Charles Beeson directed the episode written by Ben Edlund (#615).