Watch: Abigail Breslin feared she might kill Matt Damon in car scene
The 25-year-old star revealed she learned to drive specifically for the role, as well as learning French in order to play an American student living in Marseille.
"I know how to drive, kind of, but it was harder in the sense that I had to drive with Matt Damon in the car and then a camera mounted to the side and no rearview mirror," Breslin told Yahoo.
"There's a picture I have on my phone of [Tom McCarthy] giving us direction right before we start that scene and you can just see me going like this, like 'am I going to accidentally kill Matt Damon?' and Matt just like staring straight ahead, white-knuckling the side of the door.
"But he taught me how to do a U-turn, so that was pretty cool."
The film follows Matt Damon's roughneck Bill as he travels from Oklahoma to Marseille in an attempt to clear his daughter's name, after she has been imprisoned for the murder of her girlfriend.
Breslin revealed she initially didn't think she'd be able to get the role of Damon's daughter, as she lacked several of the skills McCarthy and his team wanted the actor in that role to possess.
She said: "My agent had called and said: 'Do you drive, can you swim and do you speak French?'
"I was like: 'I swim. I can swim. But I don't have a driver's licence and I don't speak French, but I can learn all of those things'."
Breslin added: "So thankfully, I don't know how or why, but Tom trusted me to do that and I immediately the next day started learning French with a coach in LA. Then I had one named Julie in Marseille, as well as a friend of mine Madeleine, who also really helped.
"Then I went to the DMV and it took me two times, but I got my licence, and here we are today."
Away from the difficulties of learning new skills, Breslin also worked hard on ensuring that there were layers and complexities to the father-daughter bond between herself and Damon.
She said: "There are 25 years before the movie starts of a complicated, intense, strange relationship that we needed to delve into so that it could motivate the way we treated each other in the film."
Stillwater is in UK cinemas from 6 August.
Watch: Trailer for Stillwater