Prinze Jr. and Gellar were already an item when "Scooby-Doo" started filming. The couple had their first date in 2000 at a sushi restaurant, according to a Facebook Live interview Prinze Jr. gave in 2016. Prince Jr. was impressed by how much food Gellar housed while on the date, including a crab that was killed right in front of them, according to E!. Principal photography on "Scooby-Doo" began in February 2001, per the Guardian, and the couple announced their engagement in April of that same year.
2002's "Scooby-Doo" was a major couple milestone for the characters Gellar and Prinze Jr. played as well. It was the first time Fred and Daphne were portrayed as an official romantic couple. Romantic tension was part of the franchise for years, and there were always fan jokes by adult "Scooby-Doo" viewers about why Fred and Daphne always paired up to look for clues. But the interpersonal dynamics of the Scooby Gang had never been a main focus of the cartoons. Later versions of "Scooby-Doo" like "Mystery Incorporated" highlighted the Scooby gang's relationships much more.
