The programme, which also stars Minnie Driver, focuses on a submarine crew as they search for new and unusual organisms.
Nesbitt, who plays Clem, told the Daily Record that the five-part series feels like a movie.
"It doesn't feel like a normal BBC drama in some respects," he said. "It's a filmic world and there's a lot of computer graphics. It's been interesting for me to deal with the 'green screen' thing. I'd never done that."
However, Nesbitt added that not all of the images were computer generated, saying: "You can't have a story like this with wobbly sets and dodgy plywood. It has to be incredibly authentic for the audience. You can see how much they have invested in this.
"It's also one of the best scripts I've read in a long time which is proved, I think, by the fact that Goran [Visnjic] and Minnie are in it too."
The Deep begins tomorrow at 9pm on BBC One.