Pitch Perfect 2” hasn’t just made more than the first film in the a cappella series. It topped its predecessor’s lifetime gross in a single weekend, after the modestly budgeted sequel debuted to a stunning $69.2 million.

The incredible growth in “Pitch Perfect’s” fanbase between installments is testament to the way that Universal Pictures organically built the audience for the quirky franchise about a group of misfit college vocalists. It’s a success story that was three years in the making, and one that relied on strong word-of-mouth that gained momentum on cable television, on-demand platforms, and through chart-topping soundtrack sales.

“We had a strong built in-audience as a result of the overall holistic marvel the film became in its afterlife,” said Paul Brooks, president of Gold Circle Films and a producer on the “Pitch Perfect” films. “People responded to it very aggressively when it screened on TV and HBO. We heard so many stories of families sitting down to watch it repeatedly. It really got under the culture’s skin.”

Before the world had ever heard of the Barden Bellas, studio executives knew that they had something special on their hands. Test screenings earned high marks, and “Glee” had made audiences accustomed to the idea of mixing humor and pop music covers, but Universal also recognized that even the best original films face steep odds at the box office. Moreover, “Pitch Perfect” lacked any big-name stars, and its charms were hard to convey in a 30-second commercial.

In advance of the first “Pitch Perfect’s” wide release in September 2012, the studio decided to build buzz through extensive screenings. It then opted for a medium-sized opening strategy, opening it in 335 locations, where it picked up $5.1 million its opening weekend, before expanding it into 2,781 theaters, where it racked up $14.8 million. Though not a blockbuster, “Pitch Perfect’s” North American lifetime gross of $65 million represented a substantial return on the picture’s $17 million production budget.

But the story didn’t stop there. What makes “Pitch Perfect” such a rarity is that it went from cult hit to mainstream blockbuster because many consumers discovered the movie on cable, on demand or by buying a copy. That’s not unlike what happened with the “Austin Powers” franchise. The spy satire was only a modest success when it opened in 1997, but audiences caught up with its quippy humor on video, and its 1999 sequel, “The Spy Who Shagged Me,” became a summer blockbuster. The major difference is that “Austin Powers” was able to capture the popular imagination at a time when Blockbuster and video rental stores were a community staple.

“It’s harder to pull this off today than it was in the heyday of rental era,” said Tom Adams, a home entertainment analyst. “There will never be a merchandising environment as great as the video store for allowing people to discover movies they missed in theaters. It’s a handicap for the business.”

The decline of DVD sales has led to a tapering off of revenues in the home entertainment space, but “Pitch Perfect” developed such a passionate fanbase on social media that it became a word of mouth hit even after it had left theaters. Universal declined to provide sales figures but said the first film was one of the top-performing DVD, VOD and pay-cable titles of 2013. It also reports that the film performed 192% above regression, which is jargon for the method studios use to estimate how many units a film should move based on historical data, its genre and box office results.

Independent analysts such as Adams estimate the film sold 2.5 million units, a number usually reserved for pictures that generate more than $100 million at the box office.

Tony Wible, an analyst with Janney Montgomery Scott, argues that “Pitch Perfect” shows there are still films that can succeed in a challenging home entertainment environment.

“You’re seeing a mixed story in how people are getting their entertainment, but it’s still an important market,” said Wible. “You may not have video stores, but you still have Twitter and Facebook, so word gets around about movies that people love but might have slipped through the cracks.”

“Pitch Perfect” didn’t just raise its profile from rentals and ticket sales. It had a musical boost. The single “Cups,” performed by star Anna Kendrick, hit the Billboard charts approximately 15 weeks after the film debuted, while a pop version of the song was released in March 2013, over half a year after the film’s release. An official music video for the catchy pop song ultimately ended up with more than 200 million views on Vevo, and the song spent 44 weeks on the Billboard Hot 100 chart, peaking at No. 6.

“We live in a world where if a consumer wants to embrace a movie, they sort of doubly embrace it,” said Brooks.

Brooks chatted with Variety from the Toronto set of “My Big Fat Greek Wedding 2,” a sequel to another low-budget comedy that managed to inspire the same kind of passionate affection on the part of its loyalists. It was an appropriate location for him to talk about the sequel’s success, because Brooks said the script for the first “Pitch Perfect” reminded him of the reaction he had to reading the early drafts of “My Big Fat Greek Wedding.”

“The script was one of the funniest and most heartwarming I’d ever read,” he said. “Intoxicating is the only word to describe my experience, and if there’s one word to describe it as far as audiences are concerned, it’s infectious. Joyfully infectious.”

The Bellas may be ending their college careers as “Pitch Perfect 2” closes, but the musical series isn’t ready to fade to black.

“We are keen to explore a ‘Pitch Perfect 3,'” said Brooks.