Aubrey Posen is a stressy, misunderstood character in Pitch Perfect. She is the leader of the Barden Bellas and one of the protagonists of the film, though despite this, she is sometimes a little hostile towards the Bellas and wants to win at all costs, sometimes bringing her to cross the line between hero and villain. Near the end, she and the girls have a heart to heart and she becomes full on hero from here on out.
In the sequel it's more friendly hostility than all out antagonism.
She is portrayed by Anna Camp.
The movie begins with the 2011 ICCA finals, Aubrey and Chloe are the juniors who are about to be the leaders of the Bellas, much to their leader's (Alice) dismay since Alice and rest of the Bellas are seniors. During her solo, she vomitted, something that leads to their loss and humiliation. She is determined to redeem herself and together with Chloe, she struggles to recruit the new members for the now humiliated Bellas. Eventually, some of the freshmen auditions. Her controlling nature starts to shown when she tells everyone should stick to the Bellas traditions by using the old songs The Bellas has been singing for years and kicks out the girls who had sex with The Treblemakers members, in disgrace. She also rejects the suggestions and advice from everyone, including Beca, believing in her own that her ways are going to bring the Bellas to victory.
When Beca, whom Aubrey seems to take a disliking from the start, shows that she does not want to be tied down to her rules, she is aware of this. Aubrey is the one who comforts Chloe when she told the Bellas that she has nodes. She also pushes everyone as hard as she pushes herself in things such as choreography and cardio. During regionals, she happily performs with the regular Bellas setlist, until Fat Amy performs the last song with full craziness, much to her fears. She kindly reminds her that next time she should stick to the original plans. She later conduct an "emergency meeting" at Beca's room, where she makes a reference to Cynthia-Rose's sexuality. She is also taking the Bellas oath seriously, even to everyone. She upsettingly asks how Fat Amy has Bumper's number. Later at semi-finals, Beca mix a different song to their setlist, which makes Aubrey furious. Then she exposes her knowledge of Beca and Jesse's budding relationship and is about to kick Beca before she quits by herself. The Bellas lost anyway.
During spring break, where the Bellas has splitting up following the loss, Aubrey, who is taking gym class, is informed that the Bellas are back in the competition after one of the competitor has been disqualified. Aubrey becomes increasingly controlling and manipulative during their comeback rehearsal, in which the Bellas are unexcitable to exercise due to her being overcritical to everyone, including her co-leader and best friend Chloe. Chloe, sick of her dominance, stands up for herself, to the point where Aubrey vomits due to her stress and anger. After she did, the club becomes a total mess where everyone is attacking each other. She, Chloe and Fat Amy are all chasing for the pitch pipe, where Lilly falls into her vomit because Fat Amy pushes her. When Beca comes back and apologize, she is reluctant at first, but later relents. She reveals her controlling nature because of her father's teaching method. She quoted him, "if you did not succeed at the first try, pack your bags." She later gives in, giving Beca the lead to take them to victory.
Aubrey later performs with the now new and improved Bellas with the brand new setlist, which impresses the commentators, audience and the judges. She hugs with Beca after the performance. Later, it is revealed that the Bellas won the 2012 ICCA finals in the next year where the audition is held in the fall. Aubrey and Chloe are nowhere to be seen with the Bellas, indicating they've graduated. So now they continue their acapella group
Pitch Perfect 2
She is now running the Lodge at Fallen Leaves, a retreat place. She is contacted by Chloe to prepare the place for the Bellas to exercise for bonding before the Worlds. She is greeted excitingly by Fat Amy and the Bellas. She greets the newest member of the Bellas, Emily. She instructs the Bellas to do the outbonds, still with her controlling nature. She tells Fat Amy that they will not sleep in a lodge or guest house, but instead a tent. During the campfire night, she tells everyone that she never thought that she would run the lodge after graduating.
She listens to the Bellas plans after they graduate, and she sings a toned down rendition of Cups with the girls. She last appears in the Worlds Competition when the Barden Bellas performs Emily's original song "Flashlight" as the final song from their setlist. She is harmonizing in the back with every former Bellas, including her former captain Alice and Emily's mother, Katherine Junk.
After suffering an embarrassing incident during the 2011 ICCA finals, Aubrey resolves to win next year's championship. Because of this resolve, Aubrey wants everything done her way. She often clashes with Beca and berates the rest of the Bellas, often blaming Beca for the group's (actually Aubrey's) failures and shortcomings. She is evidently stubborn, refusing to believe that their unchanging, bland choreography and setlist are boring the audience and the judges, instead choosing to pin the blame on anyone who tries to change anything, most notably Beca.
Aubrey is also stubborn, to an extent – even when she is at fault, she (at first) refuses to accept responsibility. She eventually defeats her pride by handing over leadership to Beca before the finals, whose changes to the group eventually win them the 2012 ICCAs.
She is also known to vomit when stressed or under too much pressure.