I Know What You Did Last Summer is one of the seminal horror movies of the 1990s. Released in the wake of Scream, it helped establish a revival of the "slasher" formula that worked so well in the '80s. The ingredients were basic. Gather together a group of attractive rising stars, toss in a masked or hooded psycho, and have most of the characters meet their demise at the psycho's hands -- or knife, or machete, or other trademark weapon.

Films like this were easy to make, but difficult to make well, which is part of why IKWYDLS proved so popular. It's genuinely good.

Directed by Jim Gillespie, the movie concerns four friends -- played by Sarah Michelle Gellar, Jennifer Love Hewitt, Ryan Phillippe, and Freddie Prinze, Jr. -- who spend Fourth of July night partying. While driving on a winding North Carolina road, they accidentally strike a pedestrian with their car. After some discussion, they decide to cover up the incident by dumping the body into the water. A year later, each of them begins receiving mysterious messages, informing them that someone knows what their secret. Soon after, the friends find themselves stalked by the Fisherman, a guy in a raincoat with a hook in his hand.

Watching I Know What You Did Last Summer is a lot of fun. Making the movie was fun too, although there were definitely a few challenges along the way. We've compiled some wild behind-the-scenes stories, as well as a few looking at the impact the film had.

Here are 20 Crazy Details Behind The Making Of I Know What You Did Last Summer.

No one wanted Freddie Prinze, Jr. for the movie

Freddie Prinze, Jr. in I Know What You Did Last Summer

At the time he was cast as Ray in I Know What You Did Last Summer, Freddie Prinze, Jr. was known primarily for being the son of a famous comedian. He had only a few small roles in movies that few people saw, plus a couple television appearances, to his name.

Landing his breakthrough role wasn't easy.

Director Jim Gillespie told Digital Spy that no one else wanted Prinze for the film because they thought he looked "too soft" and felt he "wasn't muscular enough." The actor auditioned multiple times, then went off, cut his hair, and bulked himself up a little bit.

With his new appearance, Gillespie was better able to go to bat for him, and the rest is history.

Melissa Joan Hart turned down a role

Nicole lays on her bed with her head propped up by one hand in Drive Me Crazy

I Know What You Did Last Summer assembled a cast of rising young actors. One celebrity who could have been in the movie, but wasn't, is Melissa Joan Hart.

The casting process is somewhat mysterious for audiences, but it generally involves a casting director working with the actual director to create a list of multiple potential actors for each role. They then figure out which of those actors they want to offer the parts to. If their first choice says yes, great. If they get a no, they move on to the second choice.

Hart was apparently pretty high up on one of those lists at some point. She told Business Insider that she received a formal offer from the filmmakers, only to turn it down.

Her reasoning? "I just thought it was a ripoff of Scream."

Ryan Phillippe was cast thanks to his famous girlfriend

Ryan Phillippe in I Know What You Did Last Summer

Ryan Phillippe plays Barry in IKWYDLS. Before that, he'd had supporting roles in Tony Scott's Crimson Tide and Ridley Scott's White Squall. In other words, he was a promising up-and-comer, but not yet a star.

He was, however, dating a star -- specifically, Reese Witherspoon, who was already recognized as one of the most talented young actresses in Hollywood. She auditioned for the movie, but ultimately opted against signing on.

Nevertheless, Jim Gillespie requested her advice on casting, asking who she thought the hottest young actor in town was. She understandably offered up her then-boyfriend. From that moment on, the director pursued Phillippe for the part of Barry.

This worked out well for the actor, who became very in-demand after the movie was released.

The Cast members who got married

Sarah Michelle Gellar and Freddie Prinze Jr.

On I Know What You Did Last Summer, two of the lead actors made a connection. It just didn't become love quite as fast as many fans believe.

Sarah Michelle Gellar and Freddie Prinze, Jr. got close on the set, but things never went past the level of friendship.

They didn't begin dating until two years after wrapping.

Prinze told E! News that was a good thing. "She knew what kind of guy I was," he said. "She knew what my morals were, what my priorities were and visa versa. We already kind of knew all the faults in the other person."

Once love finally blossomed, it hit hard. Prinze and Gellar have been happily married for the past sixteen years.

An obvious pop culture reference was cut out

I Know What You Did Last Summer fisherman

If you've ever eaten a fish stick, you probably recognize the image of the Gorton's Fisherman. The company's mascot wears a yellow rain slicker and a matching hat, and appears on all their products.

The killer in IKWYDLS is, of course, also a fisherman who trolls around in a raincoat and hat. There's no denying they look similar.

According to Entertainment Weekly, the screenplay originally had a joke about the villain's resemblance to the corporate mascot. During a scene in which the characters talk about possibly encountering their nemesis at a parade, she cracks, "I'm supposed to look for the fish stick guy?"

The line got cut because the director feared a laugh would undermine the story's tension.

The director was ordered to make the movie bloodier

Bridgette Wilson in I Know What You Did Last Summer

IKWYDLS more than earns its R rating with a handful of violent scenes in which the Fisherman dispatches of his victims using his hook. It's tame by the standards of other, similar horror movies, yet still violent enough to be disturbing.

Jim Gillespie didn't want to make his movie too graphic. The producers had other ideas, ordering him to reshoot the scene in which Helen's sister gets her throat cut, in order to make it bloodier. They wanted her demise to be shown in gory detail. A slight conflict ensued.

The director compromised, adding a simple pick-up shot of blood splattering a window. That gave the producers the blood they wanted, without having to show the physical act in detail.

Freddie Prinze, Jr. was the "buyer" for the cast

I Know What You Did Last Summer cast

Take a bunch of young actors hungry for their big break, plunk them down in the middle of Southport, North Carolina, far away from the glitz of Hollywood, and what do you get? Obviously, you get people who need to entertain themselves.

To cope with being in a quiet Southern town, the IKWYDLS stars would throw little parties.

There was just one hitch -- most of them were underage.

The lone exception was Freddie Prinze, Jr. who was 21 at the time, and therefore the only one with a license.

During an interview to celebrate the movie's 20th anniversary, he told E! News, that he "was the beer buyer on I Know What You Did Last Summer," tasked with getting alcohol for himself and his costars.

Jennifer Love Hewitt was scared making the movie

Watching a horror movie can be scary, but making one usually isn't. The actors know they're just pretending, are often friends with one another, and have to do multiple takes of every scene, which generally undermines the fear factor. That said, Jennifer Love Hewitt found herself legitimately frightened while making IKWYDLS.

She told the Huffington Post that she sometimes couldn't sleep when she got home because she was so unnerved from the experience of being chased by the villainous Fisherman.

Part of it was the eerie set, which was filled with atmospheric fog.

Another factor was that she barely knew Muse Watson, the actor playing the psycho. When he would run after her with a hook in his hand, it felt a bit too authentic.

Two actors feared getting fired for their hijinks

Ryan Phillippe and Sarah Michelle Gellar in I Know What You Did Last Summer

Sarah Michelle Gellar and Ryan Phillippe didn't hit anyone with a car during the making of I Know What You Did Last Summer, but they did have an incident with an automobile that had them fearing for their jobs.

Looking back on the movie twenty years later, Phillippe told Yahoo! Entertainment that he and his co-star decided to take a rental car for a spin late one night. Unwisely, they chose to drive it around on a North Carolina beach, where it promptly got stuck in a sand dune. They had to call a tow truck to get it removed.

The actor added that he and Gellar were worried the producers would fire them if they found out about the incident. Fortunately, the secret never got out, and their jobs were safe.

The most famous scene was conceived by a fan

Jennifer Love Hewitt in I Know What You Did Last Summer

Surprisingly, the most famous scene in the movie isn't one of the scare sequences. Instead, it's one where Jennifer Love Hewitt's character, Julie, becomes frustrated over being stalked by the Fisherman.

Losing her cool, she stands in the middle of the street and screams, "What are you waiting for, huh?"

The actress revealed to Us Weekly the unusual origin of that bit. "That scene was actually directed by a kid who won a contest to come on and create a moment for the movie," she said.

When presented with the fan's idea, Hewitt thought it was absurd, yet she dutifully performed it anyway. Seeing the finished product changed her mind, as she realized Julie's little tantrum worked well within the story.

A scene had to be created to fix a continuity error

Movies are shot out of sequence, which is why they sometimes contain continuity errors. Most times, such things are difficult to spot. Occasionally, one stands out like a sore thumb. The IKWYDLS filmmakers had to create a new moment in their film when they realized they were facing an enormous continuity error.

For the scene on the boat near the film's end, Jennifer Love Hewitt was wearing a sweater half the time, but just the tank top underneath during the rest of it. Scrambling to find a solution, the team built a new set part -- the boat's inner chamber. They then filmed a short scene where Hewitt takes off her sweater and uses it as leverage to open a stuck door.

This brief moment easily took care of the inconsistent wardrobe issue.

The director schemed to get a new ending

I Know What You Did Last Summer

I Know What You Did Last Summer once ended a little differently.

Jim Gillespie hated the original ending, which found Julie receiving an email saying "I Still Know."

He told Digital Spy that he shot the sequence in as boring a manner as possible, because he "didn't want it to be in the film."

His plan worked. When the movie was screened for test audiences, they deemed it anticlimactic. At this point, the studio head told Gillespie to come up with something else, something more exciting.

The director already had his replacement idea ready to go. He quickly assembled a crew to shoot the ending -- where Julie sees those words written on a steamy glass door that the psycho crashes through -- that we're all familiar with.

Related: I Know What You Did Last Summer's Original Ending Was Lame (On Purpose)

The author of book it's based on hated the movie

 

I Know What You Did Last Summer is based on a popular young adult novel by Lois Duncan.

The author was not happy about what the filmmakers did with her story.

She disliked several notable changes made to her work. The Fisherman and his hook were invented for the film, whereas on the page, the villain is just a hooded figure. The person the characters hit with their car was also changed from a boy on a bike to an adult.

Duncan especially hated the "slasher" element of the movie, as no such events occur in her book. What the filmmakers didn't realize is that the author's daughter had passed away in an unsolved shooting, which made her not receptive to entertainment that trivialized violence.

It directly influenced the casting of Cruel Intentions

Cruel Intentions DVD Cover

If it wasn't for I Know What You Did Last Summer, another '90s teen classic might have looked at lot different -- if it had even existed at all. The casting of 1999's Cruel Intentions was directly a result of the film.

That movie's director, Roger Kumble, told Cosmopolitan that he met with producer Neal Moretz in an attempt to set the project up. Moretz, who also produced IKWYDLS, told Kumble that he'd just worked with two actors who might be perfect for the lead roles. Their names were Ryan Phillippe and Sarah Michelle Gellar.

Eager to get his movie made, Kumble agreed to cast them. With two newly-hot stars attached, he was then able to convince Sony to finance Cruel Intentions. It went on to become a big hit.

You might not know about one of the sequels it spawned

I Still Know What You Did Last Summer with Jennifer Love Hewitt

I Know What You Did Last Summer spawned two sequels. You probably know about one of them. The other might come as a surprise unless you're a hardcore fan.

Rushed into production to come out a year after the original, I Still Know What You Did Last Summer brought back Freddie Prinze, Jr. and Jennifer Love Hewitt. Mekhi Phifer and pop singer Brandy were added to the cast. Although it performed respectably at the box office, the sequel was widely considered inferior to its predecessor.

Years later, in 2006, there was a second sequel.

I'll Always Know What You Did Last Summer had no big names in its cast and bypassed theaters altogether, going straight to DVD instead. It holds a 0% rating on Rotten Tomatoes.

A reboot has been in the works for years

Given how frequently popular horror franchises receive the reboot treatment, it's a bit surprising that I Know What You Did Last Summer hasn't been brought back yet. If you've been eagerly awaiting a new installment, we have some good news and some bad news.

The good news is that a reboot has been in the works for several years. There's even a finished screenplay from Mike Flanagan and Jeff Howard, the team behind Oculus and Ouija: Origin of Evil. Flanagan told Bloody Disgusting that he's really happy with the screenplay they devised.

The bad news is that there have been no new developments since they turned their script in. It's safe to say the project is still being planned, but when we'll actually see it is anyone's guess.

Ryan Phillippe received a disturbing message from the evil Fisherman

Muse Watson in I Know What You Did Last Summer

Sometimes life imitates art, as Ryan Phillippe found out the hard way. The plot of IKWYDLS finds the four main characters receiving creepy notes from Ben Willis, also known as the hook-wielding Fisherman. Muse Wilson plays Willis, and he thought it might be fun to recreate old times with his former co-star.

Phillippe told the Huffington Post that twenty years after the movie's debut, he received an out-of-the-blue direct message on Twitter from Wilson. It arrived, appropriately, on the Fourth of July -- the same day the accident that propels the movie's plot takes place.

"I think he wrote something creepy like, ‘Hello, old friend,’ or something. He was definitely tweeting in character," said Phillippe, who added that he found the message "really weird and creepy."

There was a lawsuit over the film's marketing

The cast of I Know What You Did Last Summer look on in a promotional image

For all the drama onscreen, some of the movie's biggest drama took place far from the cameras. When Sony released the first marketing materials for I Know What You Did Last Summer, they declared it as being "from the creator of Scream." That claim was a nod to Kevin Williamson, who wrote both pictures.

Referencing one of their biggest hits to sell a competitor's movie didn't sit well with Miramax, the company whose Dimension Films label released Scream. They also felt director Wes Craven deserved half the credit for creating the horror smash.

In a show of force, Miramax sued Sony over the claim. Rather than facing a costly lawsuit, Sony agreed to drop the line from all their ads.

It had a rushed production

Sarah Michelle Gellar as Helen in I Know What You Did Last Summer

I Know What You Did Last Summer was an uncommon production, given that there was a big rush to get it into theaters in time to capitalize on the Halloween horror movie business.

Generally speaking, it takes about a year to make a movie. Most are allotted three to four months for filming, followed by at least one or two months for editing. After that, there are several more months of post-production work -- scoring, sound mixing, special effects, and so on.

IKWYDLS got all this done quickly. Filming began on March 31, 1997 and lasted ten weeks. It opened in cinemas on October 17 of the same year -- a remarkable turnaround time of just six-and-a-half months.

The director didn't think of it as a horror movie

Four teenagers sit in a car in I Know What You Did Last Summer.

Most people, if asked, would describe I Know What You Did Last Summer as a horror movie. After all, it has attractive young people being stalked and eliminated by a hook-wielding psycho. Director Jim Gillespie was an outlier. He didn't think he was making a horror flick.

Gillespie told Digital Spy, "I wasn't interested in making a horror film particularly." Instead, he viewed the movie as more of a morality tale -- one about a group of young people who try to cover up a mistake and then end up paying dearly for it. "It had that core dilemma of, 'What would I do if this happened to me?'" he said.

His goal was to make the audience put themselves into the shoes of the characters, then think about what they would do in such a perilous situation.

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