The film includes short statements by influential people and celebrities such as Stephen Hawking, Ayaan Hirsi Ali, Sam Harris, Cameron Diaz, Woody Allen, Penn Jillette, Ian McEwan, and David Silverman.

"There is no through-line, we just wanted to show what it is like to be them".Gus Holwerda came to know Lawrence Krauss via Christopher Hitchens and first met him at an Origins Symposium.

Being at the event, which they viewed as a kind of Woodstock for science, Gus and Luke Holwerda conceived the idea of following Krauss around on his lectures and debates and documenting his venture in the style of a rock band tour movie.

The quality of their work with Origins eventually convinced him to go on with the movie project, which "fortuitously" began when Krauss and Richard Dawkins went on an Australian tour.

"[8] The Unbelievers includes short statements by "celebrities and other influential people" who support the work of Dawkins and Krauss, including Ricky Gervais, Woody Allen, Cameron Diaz, Stephen Hawking, Sarah Silverman, Bill Pullman, Werner Herzog, Bill Maher, Stephen Colbert, Tim Minchin, Eddie Izzard, Ian McEwan, Adam Savage, Ayaan Hirsi Ali, Penn Jillette, Sam Harris, Daniel Dennett, James Randi, Cormac McCarthy, Paul Provenza, James Morrison, Michael Shermer, and David Silverman.