Madison Iseman, star of Amazon’s reboot of “I Know What You Did Last Summer,” said she entered the franchise as a fan. 

“I had never read the book, but I was a big fan of the original movie. I kind of am a horror junkie. I’ve always loved scary movies, especially slashers from the ’90s,” Iseman, 24, told The Post.

“It’s my favorite genre to film, and to watch, too. It’s like a roller coaster. So, as soon as I saw ‘I Know What You Did Last Summer’ pop up in my [e-mail] in-box, I was immediately very excited, and wanted to put my stamp on it.”

“I Know What You Did Last Summer” began as a 1973 novel by Lois Duncan about a group of teens who, while driving home from a party, accidentally hit and kill a young boy and make a pact to never talk about the incident — but things become complicated when they start getting ominous hints that somebody knows their dark secret. The 1997 movie, which boasts a who’s who of the moment’s stars —  Jennifer Love Hewitt, Sarah Michelle Gellar, Freddie Prinze Jr, and Ryan Phillippe — has a similar plot, but the victim is an adult man.

Premiering Friday, October 15 on Amazon, the new show puts yet another spin on that plot. Iseman stars as twins, Lennon and Alison, who are part of a friend group that starts receiving nefarious messages one year after a night out that ends in tragedy. It’s a spoiler to say who their victim is in the reboot — but as they drive away from a party on an isolated seaside road, the friends don’t hit a little boy (like the book) or an adult man, as in the movie.

“When we started the show, we had only read the first four episodes. So, it was a learning experience as we went, finding more and more about our characters,” said Iseman, who’s joined by castmates such as Bill Heck (“Locke and Key”) as the twins’ dad. “It was a lot of fun — it was like a murder mystery on set as well. I really enjoyed the dynamic with the friend group. It’s interesting to watch how they interact while every character is hiding something. We all have secrets, no one is innocent [and] we’re all guilty of something. In every episode, there’s more of that story revealed.”

The series was filmed on location in Hawaii, and while the cast took the time to explore, Iseman said there was one area where her love for scary movies didn’t prevent her from being a real-life scaredy cat.

“We very much took advantage of Hawaii. We went kayaking, we went to the beach. [Other cast members] went skydiving. I didn’t, because I’m a little bit of a chicken. I like to be scared from my couch, I don’t think I like to be scared so many feet up in the air!

“The setting itself is very much a character simply because we’re all trapped and running from a killer and stuck on an island where we can’t leave,” she said. “It really is trouble in paradise.”