The show's creator Mitch Hurwitz recently revealed that he is "halfway through" writing the script for the film but Cross admitted that he will not believe the project is real until it goes into production.
"I'm more optimistic about it than I was a year ago," he told Zap2It. "[I won't believe it] until I'm standing on set and someone yells, 'Action!' That's when I'll believe it's really real."
Cross, who played Tobias, also joked about what fans can expect from the movie, saying: "It'll be the year 2087. He'll be working on a garbage barge in space. And it'll be made out of wasabi peas, which, of course, he's allergic to. But he'll be hungry..."
Hurwitz and Cross are currently working on the new Fox series Running Wilde, which will premiere on September 21.