Speaking at the Produced By Conference, Gale Anne Hurd and David Alpert spoke of NBC passing on the series and the joke that creator Robert Kirkman made to get the green light for the comic book.

From early meetings with NBC to the quick green light at AMC, Gale Anne Hurd and executive producer David Alpert recalled the beginning of The Walking Dead TV series during a Saturday panel at the Produced By Conference in Los Angeles.

Hurd, joined by senior vp business affairs at AMC Marci Wiseman and exec vp global scripted programming original development at Fox International Channels Sharon Tal Yguado, first learned of The Walking Dead comics when they were first published in 2003. But she was focused on feature films at the time and didn't know how to find an ending for a movie based on the series, so she put it on the shelf.

The early days of the comics, Alpert said, included Image Comics initially balking at the idea of a zombie title. They only gave it a green light after creator Robert Kirkman vowed to include aliens in the story -- something that by the fourth issue the comic publisher realized was a joke.

Hurd came back to the series six years later, when a colleague at her Valhalla Entertainment banner mentioned the title. She discovered that Frank Darabont, a close friend of her husband's, had the rights to the series and, with Alpert, produced a pilot for NBC.

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"We sold it to NBC, in 2005, who liked the book but wanted to do something totally different," said Alpert, who first met Kirkman at Chicago Comic-Con in 2000, where the comic scribe was promoting his first title, Battle Pope. "I learned the first time that anytime a broadcast network says, 'We're going to do something totally different,' it's not going to work."

NBC famously passed on picking up the project. Alpert was told that the network didn't want to do a zombie show. "That was one of the more frustrating things," he said of the process.

At that point, Alpert and Kirkman began looking for other homes for the property. After it had been rejected by countless cable networks, Hurd suggested that Darabont take it to AMC, which, at the time, was having tremendous success with its annual Fear Fest Halloween two-week programming block, in addition to critical hits Mad Men and Breaking Bad.

"Frank was so resistant that he didn't want to go in and go through the same experience [and be] led to believe this would be groundbreaking TV, only to have the show not go forward," Hurd said. "We pitched in October, and we were airing -- having already shot the first six episodes -- the following October."

"We were looked at like we were crazy in the very beginning of The Walking Dead -- vampires were hot and sexy and zombies, well, weren't," Fox International's Tal Yguado joked of the early days of the series.

One of the caveats, Alpert recalled, was Kirkman's insistence that the series be faithful to the comics yet different. After three seasons, the series has taken enough major detours that it's hitting the key moments from the comics but has put a major shift on several of them. Among the changes, the third-season finale featured the death of a character who is still a major player after 100 issues of the comic series.

Hurd also reiterated the creative freedom that AMC has allowed the series to take, noting that the dialogue with the network allows producers to keep key elements in scripts if the note doesn't work or there's no way to address it. Alpert, meanwhile, said there was a violent scene that was included in the series premiere.

"We didn't trust in the very beginning -- given our NBC experience -- that we had good creative partners," he said. "There's a reason why we shot a little girl in the head in the beginning of the pilot. We gave good justification early on, but we really wanted to see if they were going to let us do it."

The series -- distributed day-and-date worldwide via Fox International Channels -- continues to be a big hit globally, with Tal Yguado noting that territories like China (which, she noted, has taboos about flesh eating) find the appeal in the characters first and foremost.

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"When you pitch the concept [to international buyers] and you see the gore, it can turn people off, but it's been a credit to the characters. We've found that people embrace that it's a character and storytelling drama as well as the fanboy service we provide," Alpert said.

"Clearly the world is going through a hard time," Hurd said of the overall appeal of the series. "There's a feeling throughout the world of when is the shoe going to drop, and when it does, who am I going to be in the apocalypse. And clearly the characters we've created of who people want to be has really resounded."

Wiseman also noted that the phenomenon of The Walking Dead online inspired its Chris Hardwick-hosted show The Talking Dead, which, she said, beats most of NBC's primetime lineup. The record-breaking drama -- which hit another series best with its third-season finale -- also is a draw with women, Wiseman said, with the series only surpassed by The Voice among the demo.

Speaking to the rabid fan base, Hurd also revealed that producers receive death threats after the series kills off characters. "The fans so identify with the characters, it really is the stages of grief," she said. "First they're in denial -- 'That gunshot was off-screen; you didn't really kill her, right?' to getting angry, which is when they threaten to hunt you down and kill you."

The Walking Dead panel was a highlight of Day 1 of the two-day Produced By Conference, which is presented by the Producers Guild of America and features some of the top names behind film and television discussing their craft. Of the morning panels on Saturday, a discussion of "producers who direct" drew a large crowd due to the presence of Iron Man filmmaker Jon Favreau, film and TV producer Mark Gordon and White House Down director-producer Roland Emmerich.

Favreau said he makes a point of trying to shoot his movies in Los Angeles. "I'm very big on trying to keep production here. You get a better product here."

Elsewhere on Saturday, panels covered production tax incentives, digital distribution, video games and film finance. Stay tuned to THR for more from the Produced By Conference.

Email: Lesley.Goldberg@thr.com; Twitter: @Snoodit