Anna Kendrick had 'math whiz' mom explain lines in The Accountant

Actress Anna Kendrick had her "math whiz" mother help her understand her lines in new movie The Accountant so she could sound more convincing onscreen.

The Pitch Perfect star portrays smart accounting clerk Dana in the thriller, opposite Ben Affleck in the titular role, but she had a little trouble getting to grips with the content of her character's conversations, so she called in her accountant mom Janice to help her prepare.

"My mom is an accountant and I sent her the script... because I was like, 'You have to explain all of this to me!'" Anna explained on breakfast show Good Morning America.

"She's a math whiz and been working as an accountant for her whole life, so she was explaining all the financial aspects of it, 'cause it's really kind of a puzzle. And you don't have to be a math whiz to follow the movie, but since I was saying the lines, I figured I should kind of know what they mean, and the second I was done, I was like, 'That's gone forever!'"

Anna reveals her mom was already a big fan of the film, about an accountant who gets caught up in a deadly scandal, before it was even shot because Affleck's character onscreen is far from the stereotypical numbers man.

The star continued, "She was also excited because, you know, there's all these jokes about how accountants are boring, and so she was like, 'This is like, a sexy accountant movie! There's intrigue and fights, and it's very exciting!'"

The project marks Anna's first time working with Oscar winner Ben, and although she had "such a great time", she felt so small standing beside the tall actor, who towers over her at six foot, four inches (1.95 meters).

Anna, who is only five foot, two inches (1.58 meters), added, "He's a tall person, he's a large human being, so there were definitely scenes where I was like, 'Don't stand near me. Let's shoot across the room. They have a connection, but we're across the room!'"