David Duchovny likes to use his dogs on set. The X Files episode “Hollywood AD” in season 7, directed by Mulder himself, features a cameo from his dog, called Blue.

This isn’t the only Duchovny dog seen on TV – in the first X FIles series Blue’s father appears in the episode “Ice”.

Blue is a Border and Jersey Collie mix and apparently camera shy – in the 2004 film “Best Friend Forgotten” Duchovny used a stand-in dog. He was a German Shepherd mix called Lenny.