Reese Witherspoon Impacted I Know What You Did Last Summer's Casting Even After Turning It Down

Witnessing the release of Wes Craven's "Scream" in December of 1996 and the release of Jim Gillespie's "I Know What You Did Last Summer" in October of the following year was to witness a trend crystallize. Both films, written by Kevin Williamson, sought to breathe new life into 15-year-old slasher tropes by populating the movies with a particular type of hip-talking, self-aware '90s teen who could recognize when they were in a slasher situation. For the next few years, self-aware "hipster" teen slashers came briefly into vogue, and audiences were treated to the likes of "Urban Legend," "Valentine," "Cherry Falls," "Halloween H20: 20 Years Later," "The Faculty," and "Teaching Mrs. Tingle." Those last three, not coincidentally, were also scripted by Williamson. 

"I Know What You Did Last Summer" is based on the 1973 novel by Lois Duncan and follows a quartet of recent high school graduates named Julie (Jennifer Love Hewitt), Helen (Sarah Michelle Gellar), Ray (Freddie Prinze, Jr.), and Barry (Ryan Phillippe). While driving a dangerous road on the Fourth of July, they accidentally hit a vagrant. Rather than report the accident, the four decide to drag the body into the nearby ocean and keep their vehicular manslaughter secret. They each go off to college with guilty consciences. The following summer, Julie receives a mysterious note bearing the film's title. Did the vagrant survive? Surely he did, as a shadowy serial killer in a rain slicker and armed with an enormous fishhook is stalking and killing them. 

The film was a huge hit, and helped continue to boost the profiles of its already-rising stars. According to a 2017 interview with Gillespie, casting the film was a delicate process, and Reese Witherspoon — fresh off "Freeway" and "Fear" — was nearly cast as Julie. Witherspoon made a few suggestions of her own.

According to a 2008 documentary short on the "I Know What You Did Last Summer" DVD, Hewitt was originally cast as Helen, with the Julie role unfilled. For a moment, it looked like Melissa Joan Hart might play the lead, but she turned it down because it was too much like "Scream." Witherspoon also was offered the role, but likewise wasn't interested. Eventually, Hewitt was shifted over to the role of Julie and that part stuck. As for Barry, Witherspoon knew someone. In fact, she was dating that someone. As Gillespie said: 

"I cast them all. [Hewitt] was always going to be Julie, and she was cast first. We actually had made an offer to Reese Witherspoon first off. Reese came in and met us, but ultimately didn't want to do it. But she pointed us to Ryan, funnily enough. They were dating at this time. We asked her who the hottest guy was, in her opinion, and she said Ryan Phillippe." 

Phillippe and Witherspoon met (as documented in a 1998 Jane Magazine article) at her 21st birthday party and began dating shortly thereafter. They didn't act in "I Know What You Did Last Summer" together, but they did star in a teen version of "Les Liaisons Dangereuses" called "Cruel Intentions" in '98, which also featured Gellar. Phillippe and Witherspoon were to marry in 1999, and stayed married until their divorce in 2007. For a brief moment, the two actors were one of Hollywood's hottest power couples. Their mutual lookout seems to have started on "I Know," as Phillippe was ultimately cast as Barry, the archetypcal "jock" character.

Gillespie also talked about casting the additional two lead roles. Prinze, it seems, was initially considered too "soft" to play the part, even though Gillespie like him in the role of Ray. According to the director, Prinze screen tested multiple times, and the producers kept on turning him down. Taking the initiative, the future Ray began working out and making himself more muscular for the part. He also got a new haircut. The physical transformation was evidently enough, as Prinze was eventually hired. 

As for Helen, Gillespie reveals that, prior to Gellar, a future Academy Award winner auditioned for the part. Gillespie claims to have had trouble with casting, as the characters were teenagers, and Hollywood too often cast people in their late 20s to play such roles. He didn't want that. He said: 

"As far as Sarah was concerned, she was the last of the four to be cast. We'd auditioned loads of different people and screen-tested them, hadn't found the right person. In part it was down to the fact that I didn't want a 27-year-old playing a 17-year-old in the classic Hollywood way. There were loads of people we looked at who were just too old. Hilary Swank tested for it, who was great, but she wasn't right for the role."

Eventually he settled on Gellar who had only appeared in one previous feature film and a few notable TV supporting roles. She was on "All My Children." Her role in "I Know What You Did Last Summer" fell on the same year as the debut of the TV version of "Buffy the Vampire Slayer," an eventual cult phenomenon whereon she played the title character. Her celebrity was sealed.