The story line between Bumper and Fat Amy was not in the script. Adam Devine and Rebel Wilson would improvise during their scenes together, and Devine would often try to kiss her. This led to Devine and Wilson to create a backstory for their two characters and their relationship. The filmmakers thought the hostile, sexual chemistry between the two was funny and kept some of the scenes in the film, though according to the two actors, there was a lot that was cut out, including a reference to a one-night stand.
The song that Beca performs at her audition, "Cups (Miss Me When I'm Gone)," is a combination of a children's rhythmic percussion game played with drinking cups with a song that dates back to the late 1920s or early 1930s: "When I'm Gone," written by A.P. Carter and first recorded by his seminal folk-country group "The Carter Family." The song and the game were first combined in 2009 by the British group "Lulu and the Lampshades;" Anna Kendrick heard this version and decided to include it in her audition scene. In the U.S., the song debuted on the Billboard Hot 100 at number 93 for the week ending January 12, 2013, even before the song was released as a single. By its 32nd week on that chart, it had climbed to number 6 (for the week ending August 17, 2013).
A special screening of the film was held on 25 September 2012 at the LSU Student Union Theater, because parts of the movie were filmed on LSU's campus. The turnout for the screening was so great that only a little more than half of the students in line got in to see the movie. The producer saw that there were more students wanting to see the film and allowed a second showing immediately following the first.
Anna Kendrick said on the Late Show with David Letterman: Episode #20.19 (2012) that she learned her audition song "You're Going to Miss Me When I'm Gone" performed with the plastic cup from a viral video. It was incorporated into the movie after the producers learned she already knew how to do it.
Things Lilly says almost inaudibly during the movie: "My name is Lilly (surname), and I was born with gills like a fish," (Aca auditions) "What happened last year? And, do you guys want to see a dead body?" (First new Bellas rehearsal scene) "I did a stint in County," (In Beca's room after she is released from police custody), "I set fires to feel joy," (to Donald on the Treble's bus) "I ate my twin in the womb." (Group confessions)
At one point, while Beca is attending the activities fair and checking out the booth for the DJs (Deaf Jews), a spirited game of Quidditch (from the Harry Potter books and movies) can be seen going on in the background, including players straddling broomsticks and one player shouting, "Throw me the Quaffle!" Simulated Quidditch games have been enacted on a number of university campuses in recent years.
Kelley Jakle (Jessica) was an actual ICCA-winner in 2008 and 2010 with the USC SoCal Vocals. Ben Bram, who worked in the music department of the film, also won the ICCAs with the 2008 and 2010 USC SoCal Vocals.
Although never working together before, Anna Kendrick (Beca) and Skylar Astin (Jesse) share a connection with the prestigious performing arts camp Stagedoor Manor in upstate New York. Astin attended the camp for multiple years and appeared in the documentary Stagedoor (2006), and Kendrick starred in Camp (2003) which was based on and filmed at Stagedoor Manor.
When Beca (Anna Kendrick) enters the campus radio station for the first time, a voice is heard saying, "95.7 WBUJ," and the slogan "music for the independent mind." This is actually the slogan of 88.9 WERS, the Emerson College radio station.
Elizabeth Banks and John Michael Higgins do the announcing in the movie, and they do so in a goofy manner, a reference to John Michael Higgins in the movie Best in Show (2000), where one of the announcers also announces in a goofy manner.
In the first five minutes of the film, pre-credits, the announcer, John, says, "the women typically cannot hit the low notes, which really round out an arrangement, thrill the judges, and that can really hurt them in competition." In the climax, after Chloe has her node surgery, her voice changes dramatically. Cynthia Rose suggests she can really "hit the bass notes" now. The girls then go on to win the final competition, with Beca's new arrangement and Chloe's new deep bass voice.