It reads: "The poor guy is just asking someone to hold the door for him, since he's always carrying someone else around. After a while, 'Hold the door' became...Hodoor.
"His mind finally snapped, and now all he can say is Hodor."
That fan was Stuart A Etter who, today, is enjoying new-found fame.
Fellow fans are tweeting and messaging him asking for more predictions and his thoughts on what will happen on today's episode of the hit show.
And Etter is hoping his prediction will catch the attention of HBO, and posted a tongue-in-cheek tweet asking what his prize was.
• The next episode of Game of Thrones will air on Sky SoHo at 1pm and again at 8.30pm, and is available for streaming on Neon.