Inside sisters Dakota and Elle Fanning’s ‘fight’ on ‘Nightingale’ set

Sisterly squabble.

Dakota Fanning shared the one and only “sister tiff” she and Elle Fanning got into while filming their upcoming movie, “The Nightingale,” based on Kristin Hannah’s novel of the same name.

“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 on Tuesday’s episode of “The Tonight Show Starring Jimmy Fallon.”

“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 continued, “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 former child stars have appeared in some of the same films in the past, including “I Am Sam” in 2001 and “My Neighbor Totoro” in 2005.

Dakota, 32, explained that in those movies, they shot separate scenes, as Elle, 28, played younger versions of her characters. So they have never truly acted alongside each other — until now.

“The Nightingale” follows the story of estranged sisters Vianne (Dakota) and Isabelle (Elle), who navigate Nazi-occupied France during World War II through contrasting paths of quiet survival and active, dangerous rebellion.

Dakota admitted that she and Elle were “silently panicked” about sharing scenes 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?’”

“It’s the person that knows you the best in the world that you’re acting with,” she added. “We’re super close and we were a little silently panicked.”

The “All Her Fault” star also revealed that Elle had one request for her on set — to leave her “older sister behavior” at home.

“I had to treat her like I would treat any other actor,” Dakota explained, noting that she struggled to do so.

“The Nightingale,” directed by Michael Morris, hits US theaters on March 19, 2027.