Dakota and Elle Fanning have both been in show business since they were very young, but they've never really shared the screen together. All that will change when they take on their roles as sisters Vianne and Isabelle in the film adaptation of Kristin Hannah's bestseller, Nightingale. 

Though they both appeared in 2001's I Am Sam, Elle, 22, tells ET's Katie Krause that she doesn't count that as sharing the screen with her older sis. 

"Technically, in I Am Sam I played her at a younger age, so we weren't really acting together and I was so young, so yeah, this is the first," she says of her upcoming role in Nightingale. 

The story follows two sisters torn apart at the start of World War II. 

"Your sister knows you more than anyone. She can sniff anything out of you, she can push your buttons more than anybody," Elle adds. "It's like that dynamic is so special and unique, you're family more than anybody. That's the closest, she is my closest person. The book really explores that. They're a bit misunderstood more in the book but still we have that foundation. That we won't have to work hard for, that'll be there."

Unfortunately, the film was just about to start production when the coronavirus pandemic hit, putting a halt to filming on almost all major shows and movies. 

"We haven't shot it yet, so that's the thing. We were about to go shoot and then everything happened, so it was kinda put to a halt and I know as much as you," Elle admits. 

But that doesn't mean the actress isn't busy. Even while quarantined at home with her family in Los Angeles, Elle is hard at work promoting her new Hulu period dramedy series, The Great, in which she plays Catherine the Great. 

She co-stars alongside Nicholas Hoult, who was also on the video call to talk about their hilarious new project. 

"Tony McNamara, who is our showrunner, creator, wrote the pilot and is the man," Elle says of The Favourite scribe. "His tone and irreverence and just that dark humor is completely up my alley... It's just such a fascinating way to tell that story full of humor and really delicious language. That's so unique to Tony. And just Catherine as a character, I absolutely loved playing her. It was just the ultimate gift to be a part of this show and get to bring her to life and show our version of Catherine."

Hoult, who plays Catherine's husband, Peter III, noted that while there were a fair amount of sex scenes in the series, the physical acts were often set to highlight the conversation happening. 

"I don't think any of us make a big deal out of them. I think the thing with the sex scenes and this show is they're kind of, they're very perfunctory in terms of where the characters are aiming for, discussing during them," he explains. "They were very funny to film, a lot of them. 'Cause it was just bizarre."

Elle notes that taking on more mature roles was not a conscious decision on the part of the former child star. 

"My characters are evolving like I am," she simply states. As for whether The Great will go on to have a second season, Elle adds, "Yeah, I certainly think there's room for a season 2. Yeah, and if they wanted to do it, I would do it right away."

The Great premieres Friday, May 15 on Hulu. 

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