It was the greatest movie cameo of 2009, possibly among the greatest of all time. It was a top-secret series of scenes that had such actors as Abigail Breslin and Emma Stone sworn to absolute secrecy. Now, “Zombieland” is on DVD, and the hilarious subplot involving Bill Murray is on display for all to see.

So, with the gag order officially lifted, we had to ask the makers of the film: How did the cameo by the reclusive, eccentric star come to be? And the story, it turns out, is as hilarious as the movie itself.

“We started with Patrick Swayze,” co-writer Paul Wernick told us when he stopped by the MTV studios recently. “Patrick Swayze was the original celebrity cameo [in the script] when we wrote it, but he unfortunately got sick, and we didn’t have the opportunity to present him the script. So, once he got sick, the producer Gavin Polone and us and [director] Ruben [Fleischer] all sat down and figured ‘Who can we go to next?’”

At this point, the two writers revealed a never-before-known laundry list of actors who could play the part of themselves after the zombie apocalypse. “We had a long, long list of probably about 10 to 15 people, all of which we wrote drafts for: Joe Pesci, Mark Hamill, Jean-Claude Van Damme…”

“…Sylvester Stallone, The Rock, Matthew McConaughey,” added his writing partner, Rhett Reese – explaining where the McConaughey rumor that MTV broke came from. As it turned out, McConaughey came closest, but backed out at the last moment. “You name it, we wrote [a draft for them], and we gave it to a lot of these actors and their representatives, and they all said no for one reason or another. No one could do it.”

“We never asked the likes of Bill Murray, because we figured we’d never get Bill Murray - he’s the toughest get in Hollywood,” added Reese, remembering their moments of desperation after McConaughey pulled out. “We were out on set, and now we were actually a couple days away from shooting the scene, and we’d written an alternate version where there was no celebrity. [The four main characters] were going to just run into some zombies in the house.”

At the last minute, however, the writers discovered that it comes in handy to have a famous Hollywood veteran like Woody Harrelson on your set. “[Wernick] went up to Ruben and Woody and he said ‘Is there anyone else maybe in your Rolodex, Woody, who might be willing to do this?’ And Woody mentioned Bill Murray.”

“We wrote [a Bill Murray draft] in about two hours, out on set in Atlanta,” Reese marveled.

“But the interesting thing about Bill is that he is very hard to get a hold of; he doesn’t even have an e-mail address,” Reese added. “So we ended up sending the script to a FedEx Kinkos in New York!”

Added Wernick: “So, these guys at the FedEx Kinkos -- the guys in the aprons -- are the most powerful people in Hollywood! They have Bill’s scripts, and they read all this stuff and they decide what he does and doesn’t do!”

“Bill literally walks down to this FedEx/Kinkos, picks up the script, and reads it,” Reese finished, adding that the eccentric star only had a few minor tweaks – including the idea that he’s still a human, but wears zombie makeup to hide from the real thing. “[Murray] was a zombie in that draft [we sent]; he wasn’t alive, talking, he was a zombie. And so, he called Woody back and he said: ‘I love the script and it’s really imaginative, but I don’t really have enough to do. Is there any way I can have more to do?’”

“We re-wrote the scene so that he was alive, so he could talk,” added Reese, remembering the by-necessity genesis of one of the great movie cameos of recent times. “And then, we decided we would kill him off.”

“We sent it back to the Fed-Ex/Kinko’s,” Warnick said with a laugh. “He reads the script, loves it, calls Woody, and Woody persuasively convinces him to do the project. Two days later, he was out on set with us.”

What did you think of Murray's "Zombieland" cameo? What is your favorite cameo of all time?