It was previously confirmed that the movie will follow the show's lead characters as they take a holiday to Malia.
"We're all ready to start shooting in January," Buckley told What's On TV. "If people like the film, hopefully we might make another one."
He also confirmed that a few scenes had already been filmed on-location in Malia.
"We've filmed 20 seconds of footage in Malia," he said. "The film is about a lads' holiday so we had to rush out there just to get a shot of us walking up the strip."
It was previously announced that The Inbetweeners will return for two special episodes, following the film's release.