Dakota and Elle Fanning might "live together" during filming for The Nightingale.

The 31-year-old actress and her 27-year-old younger sister are working together for the first time on the upcoming film adaptation of the World War II novel, and they have been discussing living arrangements for the shoot.

She told Extra: "I am just looking forward to the experience as a whole, on-set and off-set. "Like, we've been talking lately about, 'Are we going to live together when we make the movie? Like, is that healthy?'

"It wouldn't be, but then we're also like, 'It'd be so weird not to.' "

The Once Upon A Time In Hollywood star thinks collaborating with her siblings on a film role will make their bond "totally unbreakable".

She said: "It's almost like we're sharing that last little piece of ourselves with each other of how we are on a set and how we are as actors and getting to share that with each other…

"So, I think we'll be totally unbreakable after."

However, Dakota admitted she will have to make sure she doesn't slip into the "bossy older sister" role on set.

She laughed: "I have to already work on not being a bossy older sister on set. I've already been thinking about that. I have to treat her like I would treat anyone else."

Elle previously described Dakota as her "best friend" whom she goes to for advice on everything, especially as they go into business together.

She told Extra in 2024: "I lean on her the most. She is my best friend, she is my number-one person I go to her for all the advice, for everything, and so I'm very lucky that I have a sister like that.

"We both understand what each other does and we understand the business, and to have that person, it's very special.

"We created a production company together called Lewellen Pictures where we produce projects together, and we're going to get to be on a panel to answer questions and to talk about our production company and to talk about the power of sisterhood."