After a big premiere week filled with a lot of big shows, we've got a full schedule to contend with. Most of the returning series took a slight hit this week, but Person of Interest stayed strong. Meanwhile Bedlam returned to the U.S. with very unimpressive numbers, and The Big Bang Theory stayed, well ... big.

You typically have a few tweaks between a pilot episode and actual series order when it comes to a TV show, as the pilot establishes a premise while subsequent episodes build on it. This season's early hit Revolution is the perfect example—and producer Eric Kripke has finally explained why one big change was made to recast a big reveal for episode two.

Eric Kripke is taking notes from The CW's Supernatural. He's snagged not one, not two, but three alums from the show to guest star on Revolution. One of them being a genre favorite who's appeared on Lost, SyFy's Being Human and most recently, Grimm.

Eric Kripke admits he's a little obsessed. It's not your normal obsession and it doesn't mean he needs to join a 12-step program. Well, at least not yet. But it is something that drove him when he created and ran the CW's Supernatural, and it's an fixation that's only increased with his latest creation, NBC's Revolution, a series that he's developed with Lost's J.J. Abrams and Iron Man's Jon Favreau.