The showrunners of popular HBO series “Game of Thrones” have advised the cast to avoid reading the books written by George R.R. Martin. Writers David Benioff and D.B. Weiss have reportedly deemed it wise to tell the cast to steer clear of the source material for the show, the book series “A Song of Ice and Fire.”

Actor Iain Glen, who plays Jorah Mormont, told that he read the first book to get an idea of what’s going to take place in the first season. After that, he has not read any of the other four published books in the series of novels upon which the show is based.

“The writers themselves, David and Dan, they didn’t particularly want actors coming to the scripts from the book, always suggesting what the book did and how it was different – I could see the glazed look in their eyes when that happened,” said Glen. Glen's character is one of the few fortunate enough to have survived all five seasons so far. Since the first episode, the TV show has deviated quite significantly from the novels.

After five seasons of the show, more actors have admitted that they have not read the novels. Now it appears that the writers have discouraged them from doing so. Glen explains that the writers wanted the actors to treat the script as a screenplay and perform based on the script and not what they know from the books.

Author George R.R. Martin agrees with the philosophy. He once spoke about the difference between a literary work and a TV show or movie and how they all need different elements to work. “There has seldom been any TV series as faithful to its source material,” he wrote on his LiveJournal blog. He was compelled to speak out after fans kept bombarding him with questions about inconsistencies between the show and the books.

“Prose and television have different strengths, different weaknesses, different requirements,” he said. He also assured fans that even if the showrunners are focused on making a great TV show and he is working on making a great novel, they are all hoping to meet at the same place in the end.

Season 5 of “Game of Thrones” has begun filming in various locations. The series is expected to return in spring 2016. The sixth book installment, titled “Winds of Winter,” is also currently in production. No release date has been announced.