It seems Lionsgate and Pantelion have finally found the instructions for how to target widespread Hispanic auds. Pantelion’s “Instructions Not Included” is the rare film that started with a medium-sized opening and continues to add theaters and increase B.O. in its fourth week.

The $34.3 million domestic grosser is shaping up as a record-breaker in several ways: It’s about to overtake Guillermo del Toro’s “Pan’s Labyrinth” as the highest-grossing Spanish language film ever in the U.S. It’s also the top limited release (under 1,000 screens) of the year, and this last weekend became the biggest Mexican film opening weekend ever in Mexico, with $11.6 million.

Having expanded to 978 theaters from 348 screens in the past few weeks, “Instructions Not Included” has played well in major markets like Los Angeles, New York, Houston and Dallas, with the highest-grossing theaters in California and Texas.

But why has this film clicked with the large Hispanic audience base where many others have not?

Much of it is due to director and star Eugenio Derbez, a Mexican TV telenovela and variety show star who also voices the donkey in “Shrek” in Mexico and starred in “Under the Same Moon,” which grossed a sizable $12.6 million domestically in 2008.

“This is his movie,” says Pantelion CEO Paul Presburger. “He has a very loyal audience, and he’s devoted so much time to marketing this movie.”

Pantelion spent less than $5 million marketing the film — a considerable sum for the specialty company, though hardly comparable to a studio’s marketing spend for a major release.

Latino audiences — the most enthusiastic moviegoing demo in the country, representing 22% of frequent moviegoers with only 16% of the U.S. population — turn out in outsized proportions for animated films and studio pics with Latino thesps like the “Fast and Furious” franchise. But many previous attempts to directly target the massive aud with Spanish-language films or using Latino talent have stumbled, perhaps because the modestly-budgeted efforts looked too much like art films and lacked family appeal.

But that’s not the case with “Instructions,” the PG-13-rated story of man whose way of life is threatened when the mother of his six-year-old daughter resurfaces, which has attracted Latino families across the country who often didn’t feel there was much for them in theaters.

“If you look at demographic changes over the last five years, in terms of where people are moving, places like North Carolina are now heavily populated with Latinos,” Presburger notes.

While “Instructions” also has marketing and distribution muscle from a big distrib (Pantelion is a joint label between Lionsgate and Televisa), the commercial dramatic comedy hasn’t tapped into non-Hispanics the way “Pan’s Labyrinth” did when it became an awards contender.

“A lot of people will say this film came out of nowhere, but we spent a lot of time and energy marketing the film to our core audience,” Presburger told Variety after the film’s Labor Day release.

“We didn’t rely just on Univision, we also bought outdoor media and radio that would hit family and women demographics.”

Targeting families — an underserved demo since “Planes” bowed more than a month ago — has been a key component to the film’s success, driven, in large part, by Derbez’s presence. Tie-in promotions for “Instructions” included the Jarritos soda located at several hundred supermarkets throughout the U.S.

Pantelion has released several other Spanish-language films, including Eva Mendes’ “Girl In Progress,” which grossed only $2.6 million last year. Its biggest release before “Instructions” was Will Ferrell’s Spanish-lingo R-rated comedy “Casa de mi Padre.”

Up next for Pantelion is the 50/50 split English-Spanish language comedy “Pulling Strings,” which bows Oct. 4.