Happy 20th anniversary, Scooby-Doo! The beloved live-action Scoob movie hit theatres on June 8th, 2002. To this day, many fans consider the film to have one of the best animated-to-live-action casts of all time with '90s teen heartthrob Freddie Prinze Jr. playing Fred, his real-life wife and Buffy star Sarah Michelle Gellar as Daphne, Marvel's Linda Cardellini as Velma, and Scream alum Matthew Lillard as Shaggy. While you may not have known it 20 years ago, you're probably aware by now that the 2002 hit film was written by Guardians of the Galaxy and The Suicide Squad director, James Gunn. In fact, Gunn took to Twitter today to celebrate the movie's birthday.