Nocturne's Sydney Sweeney and Madison Iseman Talk Real-Life High School Friendship, Sibling Rivalry (Exclusive)

Sydney Sweeney and Madison Iseman both have a strong bond with their siblings, but fortunately, it's nothing compared to the toxic, competitive relationship between their characters in Blumhouse's "Nocturne."

While speaking with TooFab during the film's virtual junket, Sweeney, 23, and Iseman, 23, who play twins in the horror flick, revealed whether or not they can relate to living in a sibling's shadow -- as well as the personal connection they share.

"Nocturne" centers on a timid, yet talented pianist named Juliet (Sweeney) who makes a Faustian bargain in order to outshine her twin sister Vivian (Iseman) at a prestigious arts academy.

Iseman opened up to TooFab about the dynamic between her and her older brother in real life.

"I mean, I can [relate] a little bit in a way," she admitted. "I have an older brother, and in high school, he was kind of the kid who had all the friends, was on every sports team and I did absolutely none of that."

"It was definitely not as malicious as V and Juliet but there was a little bit there," she added.

Sweeney, who has a younger brother named Trent, said there wasn't much competition between her and her sibling, but she admitted she "roughed him up" a bit and tried "to push him to do more."

"Nothing like Juliet or V," she explained, echoing her co-star. "I don't know anyone who is like Juliet and V, I hope no one is!"

Sweeney and Iseman went on to share how they were able to work on Juliet and Vivian’s complicated sibling bond, revealing they already had chemistry even before they shot the film.

"Sydney and I actually went to high school together," Iseman said with a smile. "So we've been friends for a couple of years. The base chemistry was already there. We've been friends for a while which actually just made it easy to be mean to each other when you’re already that comfortable together. So, we kind of just dove right into it from the beginning."

Sweeney echoed Iseman's words, saying the chemistry "was just something that organically came" to them.

The actresses also explained how they were able to portray characters who are talented pianists. While both Sweeney and Iseman have some experience with music, they were trained on how to make it look like they were musical prodigies.

"We had an instructor like a person who taught us how to look the best we could and choreograph the entire piano-esque part of it," Sweeney explained. "We both have a little bit of a music background so it was easier than it could've been."

Iseman said the movie magic was so convincing, she sometimes believed it was actually her pounding on the keys.

"We practiced for hours and hours with a coach who was just teaching us how to pretend to play these pieces like we’ve played it forever to the point where it would actually trick your brain into thinking you were actually playing it."

“Once they had the backtrack playing in the background on a muted piano, it was pretty cool," she added. "It was definitely an interesting experience. I've never really done anything like it before. It’s a new skill to add to the resume."

Watch our full interview, above, to see more from the ladies, including their favorite Spooky Season movies!

"Nocturne" is available now on Prime Video.

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