I Know What You Did Last Summer is a slasher released in 1997, a decade filled with numerous horror successes. The movie is written by Kevin Williamson, the mastermind behind Scream, and some of the plot is based on a book by Lois Duncan. The movie follows four high school friends who get into an accident where they hit a man walking on the road. Believing he's dead, the group throws his body into the water, swears one another to secrecy, and tries to move on with their lives. However, one year later, a man in a raincoat branding a creepy hook starts stalking them, making it clear he knows what happened.

This leaves the four racing to find out the identity of the man they hit while trying to stay alive as the people around them are brutally murdered. They try to investigate and learn more about the man they hit, sending them on a journey that breaks their trust in one another. The movie went on to inspire sequels, I Still Know What You Did Last Summer, and I'll Always Know What You Did Last Summer. There's also a Prime Video series loosely based on the films and original novel.

Here's a guide to the cast and characters in Jim Gillespie's I Know What You Did Last Summer.

8 Jennifer Love Hewitt as Julie James

One of the main characters in I Know What You Did Last Summer is Julie James, played by Jennifer Love Hewitt. Julie is the main protagonist in the movie and the true glue between the friend group. She has an on-and-off relationship with Ray, though the two go on to marry in the franchise, and is the love interest of Max during this movie. Julie is the character who feels the most guilt after the accident, which leads to her becoming The Fisherman's main target. She is the first to receive a note from the killer and the one most desperate to figure out who is taunting them.

Jennifer Love Hewitt became the face of the franchise after appearing in the movie's first two films, winning several awards for her performances as Julie. She is also known for her role as Sarah on the series Party of Five and Melinda on Ghost Whisperer. Her recent work includes the series 9-1-1 and season ten of Criminal Minds.

7 Freddie Prinze Jr. as Ray Bronson

Ray Bronson is Julie's boyfriend in I Know What You Did Last Summer and one of the friend group characters. He was driving Barry's car the night of the accident, but his willingness to keep the group's secret put a wedge in his relationship with Julie. The two separated for a year between the accident and the killer's return, where he spent time working as a fisherman beside Max Neurick. He also has a complicated relationship with Barry, who ends up turning on him and accusing Ray of being the killer.

Ray is played by Freddie Prinze Jr., an actor known for his role in the 1999 romantic comedy She's All That. He's also appeared in Scooby-Doo and Scooby-Doo 2: Monsters Unleashed as Fred, alongside Matthew Lillard, Sarah Michelle Gellar, and Linda Cardellini. Today, Prinze has a podcast with Jeff Dye titled Wrestling With Freddie.

6 Sarah Michelle Gellar as Helen Shivers

Helen Shivers is a main part of the movie's friend group and dating Barry Cox. She's an aspiring actress who moved to New York City after the accident but moved back home after struggling to achieve fame in the city. While she's a bit superficial, Helen is a good friend to Julie and Ray and tries to warn her sister, Elsa, about the murders. She appeared in the town's Croaker Queen Pageant Talent Competition as the host after winning the year prior, which is where she ends up witnessing Barry's murder.

Sarah Michelle Gellar stars in I Know What You Did Last Summer as Helen Shivers. Gellar met her future spouse, Freddie Prinze Jr., on the set of the film, and the two went on to star in two Scooby-Doo movies together. She's also appeared in horror films like Scream 2 and The Grudge, along with numerous other movies and TV series.

5 Ryan Phillippe as Barry Cox

Barry Cox is a part of the friend group in the movie and the owner of the car that hits the pedestrian. While he's close with the three main characters, he's violent, aggressive, and an all-around bad friend to Julie and Ray. His true colors really shine when he chokes Julie after the accident and later punches Ray, believing he is the killer. Barry is loyal to Helen, whom he supports in her acting and beauty pageants. He's one of the characters who are tormented by the killer before his death, even landing in the hospital after being hit by his own car.

Barry Cox is played by actor Ryan Phillippe, who later starred alongside Sarah Michelle Gellar in Cruel Intentions. He's also appeared in the 2006 movie Flags of Our Fathers, the USA series Shooter, and MacGruber on Peacock. Phillippe is also set to star in the upcoming horror comedy Saint Clare as Timmons.

4 Johnny Galecki as Max Neurick

One supporting character in I Know What You Did Last Summer is Max Neurick. Max is in love with Julie, even though she's dating Ray, which leads to conflict between the two men. He also has a strained relationship with Barry, whose excessive drinking habits are hard to tolerate. Even with these issues and stumbling upon the group the night of the accident, he manages to work alongside Ray as a fisherman. His death only adds to the group's suspicions of the killer's identity, as it occurs right after he is Barry.

Max is played by Johnny Galecki, an actor known for appearing on the series The Big Bang Theory. Galecki also appeared on the series Roseanne for five years before returning as David for four episodes of The Conners. His most recent film roles include A Dog's Journey and Rings.

3 Bridgette Wilson as Elsa Shivers

Elsa Shivers is Helen's older sister who owns a department store. She's a minor character in the movie, though she acts as an antagonist towards her sister, whom she's always trying to compete with. Elsa's greatest pleasures include being rude to Helen and always being right, though she's nicer to Julie than her sister. Unfortunately for Elsa, her July 4th shift at the family's store would be her last. She faces off against The Fisherman, only to have her throat slashed and her body dumped in the bathroom.

Bridgette Wilson plays Elsa in I Know What You Did Last Summer. Wilson's career started with modeling and competing in pageants before she moved on to acting and singing. Some of her most popular roles include Lisa in Santa Barbara, Ginger in Saved by the Bell, and Veronica Vaughn in Billy Madison.

2 Anne Heche as Melissa Egan

Melissa "Missy" Egan is a minor character in I Know What You Did Last Summer and the sister of David Egan. The group reaches out to her, believing they hit her brother that night, only to realize he had left a suicide note behind. David claimed the guilt of surviving a car accident where his girlfriend, Susie, was killed drove him to end his life. Yet, when Missy shows them the note, Julie realizes the handwriting is suspiciously similar to the note she received from the killer.

Anne Heche appears as the eclectic Melissa Egan. Heche was an actress with numerous credits in film and television, having starred in productions like the daytime soap opera Another World, where she won three awards, and the comedy Six Days, Seven Nights. Heche was involved in a fatal car accident in 2022 at just 53 years old.

1 Muse Watson as Benjamin Willis

The antagonist and villain in I Know What You Did Last Summer is Benjamin Willis. Ben is a fisherman and, unfortunately, the person walking down the coastal road the night of the accident. His body was thrown into the water, but he was far from dead. Ben decides to take revenge on the group who hit him and ends up appearing in both the I Know What You Did Last Summer sequels to continue his killing spree. He's sometimes just referred to as "The Fisherman" and is an incredibly abhorrent character who's willing to hurt anyone who crosses his path.

Benjamin Willis is played by Muse Watson. He portrayed the character in I Know What You Did Last Summer and I Still Know What You Did Last Summer, while Don Shanks was The Fisherman in the third installment. Watson is best known for his work on NCIS as Mike Franks and for appearing on 19 episodes of Prison Break.