When you’re fighting a legion of undead, you need reliable weapons, a plucky attitude, and — this week, at least — a bottle of Mountain Dew.

The citrusy PepsiCo soda will this Sunday appear in a new episode  of AMC’s “The Walking Dead: World Beyond,” and not only on screen. Characters will mention the beverage by name in scripted dialogue. Its cameo is part of a bid by the cable network to make one of its most foreboding series a more welcome place to one important constituency: advertisers.

“This is definitely something that we love doing and want to do more across this universe,” says Kim Granito, AMC Networks’ senior vice president of integrated marketing, in an interview, cautioning that any appearance of a product in a scene of any “Walking Dead” series “needs to be authentic to that world.”

AMC has been extremely cautious when it comes to weaving product appearances into its signature series and its various spin-offs over the course of a decade. Indeed, there has been only one major Madison Avenue property featured in any of the series since “The Walking Dead” debuted in 2010: a kiwi-green Hyundai Tucson that served as a sort of getaway vehicle designed to help the characters get out of difficult situations.

AMC’s parent company, AMC Networks, isn’t the sector’s largest player, but it oversees some critically acclaimed TV franchises, including “Dead,” “Better Call Saul” and “Killing Eve.” In recent months, the company has worked to take more control of the advertising around those efforts, including launching a “Content Room” that can develop long-form “brand films” to accompany original AMC programs or devise tailored ad appearances that fit alongside specific programs. AMC has  worked to maintain first-window sales rights when series it owns are made available on ad-supported streaming outlets such as Pluto TV, among others. In September, it unveiled a partnership with Amazon’s Twitch: a channel devoted to “The Walking Dead” universe that includes original live-streamed content related to the show.

AMC’s “Content Room” helped devise the Mountain Dew appearance along with The Content Collective, a unit of Omnicom Media Group that helps work advertisers into content.

Viewers on Sunday will see one of the “World Beyond” characters, played by Annet Mahendru, surprise another, played by Nico Tortorella  with a full bottle of Mountain Dew, cloaked in a label that might have greeted a consumer around 2010. “Is this legit?” he asks, mentioning the soda by name. “I will never stop missing these. I mean, I used to drink this like water, back in the day.”

The beverage giant helped make Mountain Dew’s day of the undead seem more realistic, digging into its own archives for an appropriate bottle label. The company also helped with one of the  old “hillbilly” figures that was used to promote the drink in the 1960s for a sign seen on a convenience store in one of this week’s “World Beyond” scenes.

PepsiCo believes the on-screen moment will strike a chord with viewers. Marketing around the beverage is “centralized around two things, culture and our fans. We believe this integration sits at the nexus of both — ‘Walking Dead’ is a highly anticipated show that remains a part of pop culture and conversation,” says Nicole Portwood, vice president of marketing for the company’s Mountain Dew business, in responses provided by email. “We believe the way the brand is shown in the episode will resonate with fans of the brand as well as the general audience,” she adds.

Over the show’s tenure, many advertisers have sought to make an appearance in “Dead” episodes, but the task is not an easy one. Advertising is all about “the world of the new,” says Scott Collins, a former president of national ad sales at AMC Networks, in an interview. But the world of “The Walking Dead” is “an apocalypse. There are no new products being produced. There is no electricity,” he explains. The demands of the plot make the process of inserting electronic gadgets or fresh foodstuffs an onerous one.  During his time, Collins recalls, the show even explored the possibility of getting an advertiser placed in a “flashback” storyline that would have explored a character’s past before zombies took over the landscape.

With that in mind, the network has instead focused on building different kinds of alliances between advertisers and the series. Commercial breaks in “Dead” are often filled with ads that refer to the zombies at the center of the programs. And there have been other unique alliances, including an augmented-reality app launched in 2017 by AMC and Mountain Dew that had fans interacting with some of the series best-known undead “walkers” and sharing them via social media. That effort, says Portwood, helped executives realize that “Dead” fans like the soda.

AMC’s new emphasis on getting products into the show comes as the series has matured. The company now manages the flagship program as well as two spin-offs. It has even articulated plans to wind down the original series by late 2022, and launch an anthology program as well as a new project centered on characters Daryl Dixon and Carol Peletier.

At the show’s peak, a 30-second ad in “Walking Dead” could cost as much as $502,500, while the same kind of spot in spin-off “Fear The Walking Dead” might go for an average of $395,000, according to Variety surveys of ad prices. In recent seasons, however, a 30 second ad in the flagship cost $135,369 and the same in “Fear” cost around $52,737, according to Standard Media Index, a tracker of ad spending. PepsiCo spent $69.3 million on advertising in the two series in 2019, according to Kantar, another tracker of ad spend.

AMC has in recent months devised other advertiser alliances. Spirits maker Diageo sponsored “Bottomless Brunch,” a digital series featuring “Fear The Walking Dead” actor Colman Domingo making cocktails.

When Hyundai placed its automobile in the series, the appearance came with restrictions. The Tucson could not be used to kill zombies. Viewers aren’t likely to see a bottle of Mountain Dew being used as a defense against a creature attack or the soda itself tapped to wash away blood. “We worked with AMC to outline a ‘comfort zone’ that provided enough creative license for the writers,” says Portwood.