Robin Williams' last outing on screen is in doubt because of fears he didn't finish recording it before he died.
Williams provided the voice for Dennis the Dog in the sci-fi comedy Absolutely Anything, which also stars members of Monty Python and British actor Simon Pegg.
The film's makers now face having to replace Williams with another actor and re-recording the entire part.
"I'm not sure Robin had completed doing his voice in the movie. He was doing the voice of my dog and I hope that he had completed it because it would be a real shame not to have him in it," Pegg told The Daily Telegraph.
Pegg added that he was devastated by Williams' death.
"It is a terrible loss. He was someone who we assumed to be a bright and vivacious and interminably happy man, but he clearly wasn't."