"I got into this trap with Sam, I set myself traps, because he had a traumatic childhood and suffered a lot – and it manifested through a stammer and a twitch sometimes."

Explaining his character, he revealed that Samwell was brought up in an environment where he was frightened to speak, which lead him to be fearful of expressing his opinion as he got older.

However, part way through the series, the actor lost control over when he would stammer. He added: “There are takes of me where it felt like it would be five minutes where I am just standing

with other the actors and I couldn’t speak and I just can’t get the words out and certain sounds would trip me up.”