Entertainment

Shhh! TV’s biggest secrets revealed

Dexter

Dexter

Jake Johnson and Zooey Deschanel.

Jake Johnson and Zooey Deschanel. (Getty Images)

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Bet you didn’t know Regis Philbin is a regular visitor to the “New Girl” writers’ room — or that Jesse (Aaron Paul) on “Breaking Bad” was originally slated to be a temporary character.

These secrets — and more — are revealed on “The Writers’ Room,” a new series premiering this Monday (10 p.m.) on Sundance Channel.

In the series, the brains behind TV’s hottest shows spill the beans on the stories behind your favorite shows.

Series host Jim Rash (“Community”) sits down with creators, producers and writers to find out, among other things, what inspired their shows, who else they considered for casting and alternative storylines for their shows’ beloved characters.

Here’s a sneak peek at some of the juiciest secrets:

Breaking Bad

* The original script was set in Riverside, Calif. But the execs at series producer Sony recommended moving filming to New Mexico instead — because of a 25 percent tax rebate. The show’s writers now consider Albuquerque an integral part of the storyline.

* Series co-star Aaron Paul (Jesse Pinkman) was supposed to be killed off during Season 1. But “BB” creator Vince Gilligan says he was so impressed with Paul’s acting that he decided to keep him around.

* On the last day of shooting, star Bryan Cranston (Walter White) got a tattoo with the logo of the show — “BrBa” — on his right ring finger to commemorate “the greatest role I’ve ever had in my life.”

New Girl

* Regis Philbin regularly visits the LA writers’ room, because his daughter, JJ Philbin, is one of the show’s writers, executive producer Brett Baer tells The Post.

* Kobe Bryant and Taylor Swift are huge fans of the show, which stars Zooey Deschanel and Jake Johnson. Bryant once came by just to watch an episode being filmed — and Swift asked to be a guest star last season. (They happily obliged.)

* Patrick Heusinger (“Gossip Girl”) and comedian TJ Miller both auditioned. “TJ Miller was up for the role of Coach, but thought he was reading for Schmidt so he shaved his chest and ripped off his shirt mid-audition,” remembers executive producer Dave Finkel.

* The “New Girl” pilot was shot in New York. But when it was decided to film the rest of the series in LA — and not to “fake NYC” — the show was rewritten to be set in California.

* Writers didn’t know Jess and Nick would have a romantic storyline until they saw the chemistry between actors Zooey Deschanel and Jake Johnson.

“There’s that moment in the pilot where the guys sing ‘Time of Your Life’ at the restaurant, and it was clear in the editing, we were like, ‘That’s a thing.’ ” Baer says.

“Dexter”

* Fans were outraged that “Dexter’s” foster sister, Deb, had feelings for him last season. But one of the show’s writers grew up in the foster care system and insisted that it happens a lot, says producer Scott Buck.

* Season 1 is based on the book “Darkly Dreaming Dexter.” One of the creators saw a small book review in The New Yorker, went out, bought it and decided to build a show around it.

* The writers always knew Deb learning about Dexter being a murderer would be a show-changer — so they delayed it as long as they could.

Parks &

Recreation

* Producer/star Amy Poehler didn’t create her Leslie Knope character. “The character was quite formed when it came to me,” Poehler says on “Writers’ Room.” “Leslie Knope was already there.”

* The audience initially felt Leslie was ditzy, says series creator Michael Schur. The writers hated that reaction, so they changed how the characters responded to Leslie.

* Parts of Ron Swanson (Nick Offerman) were borrowed from the actor’s real life. He’s a woodworker and a whiskey enthusiast.

* Much of the episode featuring Vice President Joe Biden was ad-libbed. “We improvised a lot with him,” Poehler says. “And on the last take I just leaned in for a kiss and his response is great.”