Can you believe it's been more than 20 years since Scooby-Doo hit theaters?

Yes, the live-action adaptation of the classic Hanna-Barbera series really came out that long ago and, no, we're still not over how cute Freddie Prinze Jr. and Sarah Michelle Gellar are together. And zoinks, you really are that old.

The IRL-couple, Matthew Lillard, Linda Cardellini and a CGI Scooby all hopped in the Mystery Machine to bring the beloved Mystery Inc. to the big screen on June 14, 2002.

Directed by Raja Gosnell and written by James Gunn, the movie grossed $275 million worldwide, despite some less than far out reviews from critics—and Prinze himself. 

"I've been on two jobs where I had regret doing it," revealed Prinze, who starred in the 2002 movie and the 2004 sequel, Scooby-Doo 2: Monsters Unleashed, "and Scooby was one of them."

"It wouldn't be something I would do. I have zero interest," he explained. "There was just too much bait and switch on the first one. The studio was not honest with me in any way shape or form."

Indeed, Scooby-Doo was originally scripted to be much "edgier," according to director Gosnell, who previously told E! News that he and Gunn "never got a chance to show the movie we made to the audience it was intended for" after the studio decided to make it a far more family-friendly flick.

While he didn't provide any Scooby snacks, Gosnell did reveal 22 secrets about the movie, including how he ended up casting one of Hollywood's most beloved couples as Fred and Daphne, which stars had to dye their hair and the real reason a kiss between Velma and Daphne ended up being taken out of the final version...

1. Plans for a live-action adaptation of Scooby-Doo first began in 1994, with various directors and actors, including Mike Myers and Jim Carrey, being attached to the project before Raja Gosnell was hired in October 2000.

2. James Gunn, who would go on to helm superhero hits such as Guardians of the Galaxy and The Suicide Squad, wrote the script, which was initially R-rated. But Gosnell knew it needed a tweak. "We're not crazy, no one was going to do an R-rated Scooby do because why would you?" he said. "We did get an R-rating from the MPAA board at one point. There was some misunderstanding on some language, but we cleared that up."

3. While they didn't set out to make an R-rated movie, Gosnell and Gunn, who were both fans of the Hanna-Barbera animated series, were aiming to make a PG-13 parody of Scooby-Doo. "The best way to say it is what Shrek was to fairy tales and what Austin Powers was to James Bond," Gosnell described, "James' script of Scooby-Doo was to the Scooby. It had all those winks and acknowledgments and self-referential bits."

4. Wanting to make the movie for fellow fans of the original cartoon, their initial version had, Gosnell revealed, "some winks to Velma's sexual orientation and there were more pot jokes" before the studio ultimately decided it wanted to market the movie to a different audience.

"They wanted to sell the movie to what the current demographic of Scooby-Doo was and that was young kids and their parents," Gosnell recalled. After the movie was screened for a test audience of "pretty conservative" parents in Scottsdale, AZ. "didn't play well at all," the director said "that started the first scramble to take out all of the 'is Velma gay?' references. We just had to do our best to protect the movie and make the best movie we could under newer guidelines."

5. One major change was taking out all mentions of the word "soul" after they received some "pretty hard pushback from religious people" during the test screening, Gosnell said.

"Originally, none of us thought about this while we were shooting, but the things that were pulled out of the people to go into the demon, we called those souls because it was a soul-sucker machine," Gosnell explained. "But we had a screening and we had some pretty hard pushback from religious people. We were like, 'No, it's not meant to go there!' We basically had to go through the movie and take out every reference and make it protoplasm."

6. Another scene that hit the cutting room floor was a kiss between Daphne and Velma as the Scooby gang exchanged souls. Excuse us, protoplasms. 

"It was 100 percent a studio decision," Gosnell said of the kiss being scrapped from the final cut. "My only regret in the whole process is that we never got a chance to show the movie we made to the audience it was intended for."

7. When it came to casting his Fred, Daphne, Velma and Shaggy, Gosnell said he landed his "dream cast" in Freddie Prinze Jr., Sarah Michelle Gellar, Linda Cardellini and Matthew Lillard, respectively.

"I can't see the movie without that cast. We talked to a lot of people, but it was who would audiences like to see in this role and basically who best embodies it," Gosnell explained. "And we saw a lot of people for Shaggy and as soon as Matthew walked in it was just like, 'He's Shaggy, yep! Done.'"

8. To nail Shaggy's scratchy vocals, Lillard "had to scream for like five minutes every morning," Gosnell revealed.

9. The creative team didn't set out to cast a real-life couple as Fred and Daphne and it was Prinze and Gellar who brought the idea to the filmmakers.

"When the call came in that Freddie Prinze Jr. wanted to play Fred and we met him and he was like, 'Oh man, my whole life I've been called Fred!'" Gosnell recalled. "He just had such an affinity for it and with Sarah Michelle was interested in Daphne, it was a slam dunk."

While Fred and Daphne were never officially a romantic pair in the original series, Gosnell said, "Audiences always put those two together as a couple, so to have a real life couple already in place, it just felt like the audiences are really going to like this."

10. Prinze and Gellar had no hesitations about starring in the movie together, Gosnell said. 

"The idea of them doing something together, playing a couple they grew up watching was part of the appeal for them," the director explained. "It wasn't a negative, it was a huge positive."

11. Of course, to play Fred, Prinze had to dramatically change his hair. "He's tall, dark and handsome, right?" Gosnell said. "But Fred has to be blonde and he has to wear the ascot and we wanted to honor the original profiles of the characters, so he dyed his hair, and it was hard on him. I think we lightened his eyebrows too, and that was just a process."

For the 2004 sequel, Prinze "just shaved his head and we wigged him," Gosnell admitted. "He said, 'I'm not doing the dye thing again, guys! So let's just figure out something else.'"

12. The casting department was having a little trouble finding an actress to play Mary Jane, Shaggy's love interest, before they found a then-unknown Isla Fisher, said Gosnell: "She came in and she read with Matthew and we all fell in love with her in the first 10 seconds."

13. The character originally had a different name, but was changed to Mary Jane because Gunn and Gosnell wanted to get in another pot reference.

14. Naturally a redhead, Fisher wore a blonde wig because "we didn't want her to be in the Daphne zone," Gosnell explained.

15. To film the scenes between the actors and the CGI-rendered Scooby, production lined up the shots with a giant stuffed animal or used a giant stuffed bag if it was a scene in which Lillard was holding the dog. 

"What you're really watching is Matthew just being a fantastically aware actor, just always sensing Scooby is there," Gosnell said. "Matthew made him real more than anything else we could have done. He made it so easy for the animators to just put Scooby in there."

16. While Neil Fanning was originally hired to provide Scooby's vocals during rehearsals, Gosnell revealed "he just worked so well that he ended up being the voice in the finished movie." 

17. "One of the more controversial decisions was that we made Scrappy the villain," Gosnell said, explaining that as a fan of the original series, "Scrappy ruined the series. It just seemed like the moment Scrappy came on, we were out. So it was just a brainstorm between James and I where we were trying to figure out the final twist. Just out of the session, it was like, 'F--king Scrappy! Like yes!'"

18. As for the passionate response from some fans about Scrappy's evil turn, Gosnell said, "I know people younger than us that really like Scrappy, so I think that was part of the controversy. Like, 'Ugh, why did you do that to Scrappy?!' But it was exactly like the character itself. The twist was widely debated on what era of Scooby you watched. But enough people hated Scrappy, so we were mostly applauded."

19. Mark McGrath and his band Sugar Ray's random appearance as a possessed band wasn't so random back in 2002.

"It has lessened now, but this was back in the day where you had to have a soundtrack for a big movie," Gosnell shared. "Mark McGrath came from like, 'Hey, we have a scene where James has written in a band. Can we get a real band?' They did a great job. They had a lot of fun with it when they got to be demons."  

Naturally, they also got singer Shaggy to perform the main theme song, with Gosnell joking, "That wasn't going to not happen."

20. Pamela Anderson also made a cameo as herself in the beginning of the movie, which is a nod to the random celebrities that would appear on the animated series.

"We just thought, 'Well, who's the most of-the-moment person who would be the most random person to ever step out of the van?'" Gosnell said. "And, of course, Pamela Anderson! She flew all the way to Australia for that cameo. It was fantastic."

21. While there were initially plans to make a third movie, Warner Bros. shelved the project "because the second movie didn't gross as much as the first movie and so it was like, 'Well, let's step back and rethink this,'" Gosnell said, adding he would've done another film "in a heartbeat."

22. Despite the studio making significant changes to the original idea for a more subversive take on the series, Gosnell doesn't harbor any ill will. 

"I don't fault the studio for those decisions because Scooby-Doo is a big piece of intellectual property for them," he explained. "He's on cereal boxes and tennis shoes and backpacks, but when they greenlit the movie, they were okay with doing this parody. And at the end of the day, they didn't want to risk tainting the brand, so to speak, for this movie. That's the decision they made and we altered the movie to deliver to that audience."

This story was originally published on June 14, 2022 at 3 a.m. PT.