The poor pooch, called Elmo, was a rescue dog and was due to be put to sleep because a suitable owner could not be found.
But movie-makers saved his life and offered him a slice of fame by casting him as Astronaut in the upcoming children's adventure story.
Ricky Gervais, who voices the character, tells British TV show This Morning, ""He is a rescue dog. They were going to put him down, so the film saved him and made him a star. So, kids, if you don't go and see this film we are going to put him down. We're not! That's not true.""