Faced with the challenge of selling zombie romantic comedy “Warm Bodies,” Lionsgate/Summit goosed its aggressive word-of-mouth campaign via a growing mini-trend: ultra-targeted sneaks hosted through exhibitor loyalty programs.

Sneaks have long been a common way for studios to build and gauge pre-release interest, and have become even more essential in the social-media age. But using exhib rewards plans, such as AMC’s Stubs and Regal’s Crown Club, is a relatively new method of ensuring that advanced screenings are well-attended — and well-stocked with avid moviegoers.

“Five years ago, the loyalty programs consisted of an executive’s mother and relatives,” said one distribution exec. “Nowadays, these programs, with millions of members, have become a major part of a release strategy.”

Tapping into the loyalty-program faithful provides advantages for both exhibitors and studios: Theater chains curry favor with their most loyal customers by offering them the best advanced screenings, while studios can expect higher turnouts for their sneaks — which can be tough to fill, believe it or not — because invitees tend to be enthusiastic, highly motivated moviegoers.

“It’s always been a strategic move,” said Sun Dee Larson, veep of film marketing and communication for AMC. “We knew that studios already were executing screening programs, so we thought, ‘What a great, supplementary opportunity for them.’ ”

For “Warm Bodies,” which exceeded expectations with a $20.4 million Stateside debut, Lionsgate partnered with AMC and Regal to offer loyalty members a screening nearly a month in advance. Most other rewards-hosted sneaks haven’t had such a lengthy lead time, however.

Universal sneaked “Les Miserables” to AMC rewards members a few days before it release, as did Fox with “Parental Guidance.” In general, these types of previews happen a few days — if not a couple of weeks — in advance of a film’s release. Social media marketeers agree that weeks-early sneaks are far superior when building word-of-mouth.

Lionsgate and AMC joined forces first sneaking “Warrior” in 2011. The studio had been having difficulties filling sneaks, based on the tricky nature of marketing the MMA fighter-family drama. But by partnering with AMC and its rewards program, the studio ultimately secured a sneak preview at 85% capacity.

Regal, meanwhile, has worked with five distributors over the past eight months.

“Since I came onboard with Regal last summer, we’ve increasingly partnered with studios for mutually beneficial promotions, such as these screenings for loyalty club members,” said Regal marketing chief Ken Thewes. “Regal Crown Club members have enthusiastically responded to the opportunity and packed the auditoriums.”

Just as with regular sneaks, the rewards-hosted screenings are held nationwide, at anywhere from 90 locations (as it was with “Warrior”) to 10-20, depending on the studio’s needs.

Along with Regal and AMC, studios are working with Cinemark, all of which send targeted emails to customers that promote daily discounts and events, including sneak previews.

“We’re definitely trying to reach every single one of our members,” AMC’s Larson said. “We wanted to find other ways to reward them with exciting benefits.”