“Psych” may have only come to an end in 2014, but its producer and star James Roday says that the team behind the USA dramedy had been approached about doing some kind of reunion a couple of times before they finally agreed to “Psych: A Movie.” Though what made them agree to it this time ultimately came down to the timing (“We were away long enough to be missed but not forgotten,” Roday tells Variety), Roday also says that when he and executive producer Steve Franks talked about the idea, Franks “already had five acts” of a new story in his head.

“It needed to be a throwback to the early capers of ‘Psych’ that put ‘Psych’ on the map and helped grow the audience and kept us on the air for eight seasons,” says Roday. “So the idea was, let’s do classic, early Shawn and Gus caught up in a caper and build from there.”

The element of the movie that was most important to both Franks and Roday was that it be a “true love letter” to the fans of the show, without whom they feel it would not even be possible.

“When shows reunionize, as the term is now, sometimes they just reset the arcs and the characters go back, and we didn’t want that at all,” Franks says. “We wanted everything that happened in the show to matter.”

So while “Psych: The Movie” picks up three years after the events of the finale, “everything you saw in that last episode plays into” the movie, Franks says. “It was taking those things and building on that. We’ve got more action and more comedy and more drama and danger than we’ve ever had before.”

The two-hour running time allowed the team to not only go bigger with some of its action sequences, but also to include more moments that die-hard fans (aka “Psych-Os”) would recognize and to let humorous bits build and then breathe.

“We’ve doubled the real estate,” Roday says. “To do a 29-point turn in the car instead of an 11-point turn, to have a scene where Shawn and Juliet lie in bed — these are the luxuries that come along with making a two-hour special that you just don’t have when you’re cranking out a murder of the week procedural.”

The movie also allowed Franks and Roday to pay off a long-held dream — of paying tribute to David Bowie, who they both wanted to have on the show during its initial eight-year run. The rock legend passed away in 2016, but he lives on in “Psych: The Movie” through the aptly-named Thin White Duke character, portrayed by Zachary Levi.

“We were basically going to do Bowie, and Zac was perfect because he’s tall and thin and so enthusiastic,” Roday says. “He does not half-a– it, so when we said Bowie, it was everything — the hair, the accent, because why wouldn’t it be? He came up with a really interesting, outside of the box creation.”

The movie also pays tribute to a beloved member of the “Psych” family in Timothy Omundson, who has been recovering from a stroke he experienced in early 2017. Roday says that it was initially “bittersweet” to step back on set without Omundson, but the longer the cast and crew worked, the more they realized they were doing the project for him.

“He was there in spirit,” Roday says. “So it became something that we were all able to rally around, and it kind of became a battle cry the longer we were on set.”

The creators also wrote a special cameo for Omundson that they shot after the movie had wrapped. “We’d seen the movie without his part and we’d gotten used to it at that level,” reveals Frank. “In a sea of emotional things that had happened, it gave it a whole other level to be able to include him.”

Roday says he loves the scene because it’s a “classic Lassiter” moment. “He’s telling Juliet, who will always be Luke to his Obi-Wan, ‘You’ve got this,'” Roday says. “But it’s also him telling the Psych-Os, ‘Hey, I’ve got this.'”

When “Psych” first ended, neither Franks nor Roday would have expected a movie like this to be a possibility. But now that they’ve done it, they’re not ruling out the possibility of returning once more.

“I think our fans are going to dictate how many of these we’re going to make,” Roday says. “We’re never going to say no because we’re all of the constitution that we were the luckiest group of people that ever got put together to make a show. I don’t think we’ll ever take that for granted. Regardless of what any of us are doing, we know that what we’re doing is because of this show. So as long as there’s an appetite for it, we will always come back to deliver for our fans.”

“Psych: The Movie” airs on Dec. 7 on USA.