Anna Kendrick said she has "PTSD flashbacks" when talking about Pitch Perfect and described the filming schedule as "chaotic".
The 37-year-old actress starred as Beca Mitchell in the musical comedy series and earned widespread recognition for her performance, which many critics described as "splendid".
While the films were major commercial successes, behind the scenes things weren't quite as glamorous as they seemed.
"For all three movies it got worse as it went along," Anna said as she opened up about changing scenes and having to learn choreography at the last minute.
The star said the first movie had been "so crazy and disorganised", but there had been hope that by the second film they would be a "well-oiled machine".
Rebel Wilson poses with adorable rarely-seen daughter Royce at friend's wedding"Nope! The second movie was crazier and weirder and things kept changing, like the music kept changing, which meant the choreography kept changing. And then the third one was a total free for all," she told Heat magazine.
Anna joked: "The finale of number two, I believe we learned the choreography that weekend. It was simple, but still. I don't know, it was chaotic, I'm having PTSD flashbacks just talking about it."
She added that memorising choreography only got worse as the films went on because the stars were "getting older and our brains were declining".
Anna recently revealed she had made embryos with a toxic ex-boyfriend before their relationship ended.
She chose not to identify the partner, but described him as "for all intents and purposes, my husband".
Appearing on the Armchair Expert podcast, she told hosts Dax Shepard and Monica Padman that her former partner would "scream" at her until she sobbed.
He later told her he had feelings for another woman.
Anna eventually started going to therapy which she says helped her to end the unhealthy relationship.