Few (if any) box office analysts accurately predicted this weekend's top five movies, since one of them was a film few pundits had ever heard of: a Mexican dramedy called "Instructions Not Included," starring Mexican comic actor Eugenio Derbez. It opened on just 347 screens, but by Sunday, it had earned an estimated $7.5 million, good for fifth place. (It was projected to earn $9.3 million by the end of the Labor Day four-day weekend.) It averaged a robust $21,614 per theater, more than any other film this weekend, and more than three times as much as any of the wide-release films currently in multiplexes.

How did a film not on any pundit's radar become such an instant box office hit? The answers suggest that there's a large, untapped, Spanish-speaking movie audience in America, hidden from view by an industry blind spot. Here are some of the factors behind the success of "Instructions":

Eugenio Derbez: English-speaking audiences may barely know him, except from his dual role in Adam Sandler's "Jack and Jill" or his supporting role in Rob Schneider's short-lived sitcom "Rob." But in Mexico, he's been a huge TV comedy star for 20 years. "Instructions," which has a "Kramer vs. Kramer"-like plot about a man whose estranged ex suddenly reappears and fights him for custody of their daughter, is entirely Derbez' baby. Not only does he star, but he also directed, co-wrote, and co-produced the film. He has 3.2 million followers on Twitter (in fact, he used Twitter to find his pint-sized co-star, Loreto Peralta), so even if Hollywood insiders didn't know much about the film, his massive fanbase certainly did.

Word-of-mouth: Critics have been mixed about "Instructions," which combines cartoonish slapstick with weepy melodrama. But audiences ate it up. It earned a rare A+ at CinemaScore, meaning it's enjoying the strongest possible word-of-mouth.

The Spanish-speaking market: The film's distributor, Pantelion Films, is a division of mini-major Lionsgate that specializes in films targeted toward Hispanic audiences, like Eva Mendes' family drama "Girl in Progress" (which featured Derbez in a supporting role) or Will Ferrell's Spanish-language comedy "Casa de Mi Padre." Most of these made a modest splash, but "Instructions" is already the company's biggest hit after just three days. It seems to have cracked the formula for reaching Spanish-speaking audiences in America. Which is, apparently...

Crossover: "Instructions" is a bilingual movie that has one foot planted in Mexico, the other in the U.S. The story sees Derbez' character move from Mexico to Los Angeles. His daughter Maggie (Peralto) is a blond-haired, blue-eyed moppet who speaks perfect Spanish and unaccented English. There are some jokes and references that English-speaking audiences won't get, but they'll get most of them. The parent-child love story at the heart of the film is certainly universal, and that's something Derbez was counting on when he crafted the film, citing the example of Roberto Benigni's heartstring-tugging Italian-launguage family comedy and international smash "Life Is Beautiful." "I know I can count on the Hispanic audience but now I want to reach the general market," Derbez told Fandango in a recent interview. "I think this movie could be the start of something." Looks like he was right.

Instructions Not Included- Trailer No.1
Instructions Not Included Movie Poster
Instructions Not Included
In Theaters on August 30, 2013

An irresponsible playboy (Eugenio Derbez) must grow up quickly when a former lover gives him their daughter... Read More