The actor, who plays Kryten in the cult series, said that the show is difficult to make.
Speaking to DS, Llewellyn admitted: "I've done [shows] that involve danger and hardship, but nothing remotely as tough as Red Dwarf.
"It's the toughest gig I've ever had, and the crew and production said the same. It's a very ambitious show to make on a relatively small budget."
He added: "The money definitely goes on the screen - there's no luxury behind the scenes!"
Since the last series of Red Dwarf, Llewellyn has presented Scrapheap Challenge and had guest parts in Hustle and MI High.
> Click here to read our full interview with Robert Llewellyn