I Know What You Did Last Summer TV series: Release date, cast, trailer and latest news

Inspired by both Lois Duncan's 1973 novel and the hit 1997 slasher film, Amazon's I Know What You Did Last Summer will be a modern take on the story of teenage friends who are stalked by a brutal killer one year after a terrible accident.

With horror maestro James Wan on board as executive producer, the series is sure to be suitably spooky - and best of all, it's set to arrive in time for Halloween.

Here's everything we know about the I Know What You Did Last Summer TV series.

I Know What You Did Last Summer TV series release date

Just in time for spooky season, the first four episodes will be released on Amazon Prime Video on Friday 15th October 2021.

There will then be a month of spine-tingling slasher scares, as the following four episodes will be released weekly on Fridays until the finale on 12th November.

I Know What You Did Last Summer TV series cast

The lead role - made famous by Jennifer Love Hewitt in the 1997 original - this time goes to Madison Iseman, best known for playing Bethany Walker in the Jumanji franchise. Iseman will be on double duty playing both Lennon and Allison, who will likely be twin sisters - or perhaps something more sinister...

She will be joined by Briane Tiju - who had previous slasher experience in anthology series Scream - as Margot, while Dragonfly's Ezekiel Goodman will appear as fellow troubled teenager Dylan.

Rounding out the cast are Ashley Moore (Popstar: Never Stop Never Stopping) as Riley, Sebastian Amoruso (Solve) as Johnny and Fiona Rene (Stumptown) as Lyla.

There's some frightfully good talent behind the camera also - James Wan, who co-created the Saw and Insidious franchises is an executive producer, as well as Erik Feig and Neal H. Moritz, who produced the original 1997 film.

I Know What You Did Last Summer TV series trailer

The trailer was released in September 2021 and teases lots of suspense and even more slasher scares - complete with an Olivia Rodrigo soundtrack to highlight the modern teenage feel the series is aiming for:

You can also watch the trailer while the cast reacts to it, Gogglebox-style:

I Know What You Did Last Summer TV series plot

I Know What You Did Last Summer will have the same premise as the original book and 1997 film, which saw a group of teenagers accidentally cause a fatal car accident on their graduation night. After covering it up and sharing the secret for a year, a brutal killer starts stalking them, revealing the dark side of their small town - and themselves.

However there will be a few changes for this series, with creator and writer Sara Goodman explaining that the extended running time will be used to explore the characters so they are "not just running from a stalker”.

“They're also are having relationships and they’re having issues with their families, dealing with their real lives,” Goodman said during the Comic-Con@Home 2021 Amazon panel. “There’s more than just the mystery of who’s after them. It’s very much a mystery of who they really are.”

Goodman has also spoken about wanting to update the book - now nearing fifty years old - for modern times, and not just by incorporating selfies and smartphones.

"The novel was of its time and the movie was very much of its time and I wanted to make a show that’s of this time," Goodman said. "And so, no one is just a jock. No one is just a smart girl. No one is just a bitch. People are really layered and everyone has different pieces of themselves they show to different people at different times.

"They’re much more diverse and people are more complicated, and I think the cast is very much representative of those deeper, layered characters. And so is the story."

The original I Know What You Did Last Summer was released in 1997 and starred '90s icons Jennifer Love Hewitt, Sarah Michelle Gellar, Freddie Prinz Jr. and Ryan Phillipe.

Goodman revealed at the Comic-Con@Home 2021 panel that there were easter eggs hidden throughout the series for fans of the original hit film, while Phillipe told ComicBook.com that he would be "open to cameo" - so could we see an I Know What You Did Last Summer crossover?

I Know What You Did Last Summer will premiere on Amazon Prime Video on Friday 15th October 2021. You can sign up for your 30-day free trial and pay £7.99 a month after that.

For more to watch, check out our TV guide or visit our Drama hub for the latest news and features.