“We have been working on that for a while. It’s been hard, because we all have jobs, and some of them are extremely taxing,” he said, no doubt alluding to his own film work, Harris’s work on “How I Met Your Mother” and Fillion’s work on “Castle.” “But we have had a vision of the thing for a while, we have been working on it, we have a bunch of songs and a few scenes. We need a little free time and right now that’s plenty hard to come by.”