Even though Psych has only been off the air for a handful of years, it's still a little bit of a miracle that Psych: The Movie managed to get made. After all, this is Hollywood, where actors move on and commit to other projects at light speed, making the coordination of schedules next to impossible.

The cast of Psych pretty much willed this movie into existence though, which creator Steve Franks says is a testament to how much this close-knit group of people loves working together.

"Last summer when I got the call saying, 'Hey you guys want to try to do it?' we realized there was actually a window eight months later," Franks told TV Guide. "That gave us enough time to come up with a story, pitch a story, write a script, get it approved, have them find the money to make it and put it all together. So it was one of those things that we all willed it to happen because we just like being together... We were going to find a way to do it one way or the other."

Still, getting the band back together didn't come without its complications. Dulé Hill was apparently juggling roles on multiples series as well as a few on-stage commitments, and various guest stars needed to squeeze room into their schedules to make their appearances happen.

Case in point: John Cena.

Cena was a one-time guest star as Juliet's (Maggie Lawson) brother Ewan O'Hara in Season 4, but when he was called up to appear in the movie, he was eager to reprise his role.

"John Cena moved heaven and earth to come up and do this," Franks says. "I've never seen so much effort by a person to come up and make an appearance. He was doing two other movies at the same time in Atlanta, and came up to Vancouver on a weekend on his off-shooting day to come up and shoot his sequence, which was so much fun to do."

James Roday and Dulé Hill, <em>Psych: The Movie</em>James Roday and Dulé Hill, Psych: The Movie

There are so many other guest stars who play a part in the film, and all of them are preposterously amazing in their own special way. The one you'll probably enjoy most though is definitely Westworld's Jimmi Simpson.

Simpson was introduced to the show in Season 3 as Mary Lightly, a slightly obsessive character who helps Shawn (James Roday) and Gus (Hill) solve the case of the missing Mr. Yang. He was later stabbed to death in the Season 4 finale, but that won't stop him from making an appearance in Psych: The Movie.

"From the beginning, we started making a list of who we would want to have come back, and Jimmi was the first name on that list," Franks says of Simpson's quick cameo, which just so happens to be a scene that kind of steals the show. In fact, it's a moment that's so impressive, Franks is already angling to get him back for more sequels down the line. "Now it's like, Jimmi has to be in all of them!"

As far as major challenges go, there was none so difficult — or so terrifying — as the stroke Timothy Omundson suffered just before production began. Although it soon became clear that Omundson would make a full recovery, people still fretted that fan-favorite Lassiter would no longer play a part in the movie.

Luckily, that's not something Franks would ever have allowed to happen. And thanks the gods, because Omundson may have only managed to film a single scene for the movie, but trust us when we say it is honestly one of the most emotional moments of the whole story.

"Tim had had the incident the day before we were flying up to begin prep. We didn't know a whole lot about what was going on and our first concern was, 'Is he going to be okay?'" Franks explains. "We weren't going to make the movie if Tim hadn't bounced back as much as he did so quickly.... I got on the phone with James the next morning and we started talking about the way that we could do it and have Tim participate when he was ready, for as much as he was ready and prepared to do. We figured out the way to do that scene and to make it important and vital to the story at its most important point, and we were able to shoot it at a little bit of a later time and make it the best for Tim."

Psych: The Movie airs Thursday, Dec. 7 at 8/7c on USA.