Dakota Fanning has shared the details of a singular disagreement between herself and her sister, Elle Fanning, that occurred during the filming of their upcoming movie, "The Nightingale."

Speaking on "The Tonight Show Starring Jimmy Fallon," Dakota described the incident as the only "sister tiff" they experienced while working together on the film, based on Kristin Hannah's novel.

"Right towards the end, there was a scene we were doing together, and it was this really hot room and we were on this couch, and I was like, ‘Move your leg!'" Dakota recalled. "She was like, ‘My leg has been here all day!' And I was like, ‘No, it hasn’t. Get off of me! I’m too hot. You’re sweating on me’ … I was like, ‘Stop talking!'"

Dakota added that the crew found the exchange amusing because the sisters had maintained a professional demeanor throughout the entire production until that moment. "It was the only quote-unquote ‘fight’ — but the crew was dying because we had kept it so together the whole time. It was totally a sister tiff."

The sisters, who previously appeared in films like "I Am Sam" (2001) and "My Neighbor Totoro" (2005), had never acted alongside each other in scenes before "The Nightingale." In their prior collaborations, Elle played younger versions of Dakota's characters, meaning their scenes were shot separately.

"The Nightingale" portrays estranged sisters Vianne (Dakota) and Isabelle (Elle) navigating Nazi-occupied France during World War II. Their paths diverge between quiet survival and active rebellion.

Dakota admitted that both she and Elle felt a sense of "silently panicked" anticipation about sharing the screen for the first time. "We were very quietly nervous about it. I think we didn’t really want to tell the other one how nervous we were," she explained. "We were like, ‘Are we going to laugh? Are we going to be able to keep it together?'"

She elaborated on the unique dynamic of acting with a sibling, stating, "It’s the person that knows you the best in the world that you’re acting with. We’re super close and we were a little silently panicked."

Before filming commenced, Elle had specifically requested that Dakota set aside any "older sister behavior" while on set. Dakota noted that she found it challenging to adhere to this request, as she had to treat her sister as she would any other actor.

"The Nightingale," directed by Michael Morris, is scheduled to be released in U.S. theaters on March 19, 2027.