The Creators Know How The Story Ends
Although readers of the novels will have to wait until the final two books are written and released before finding out how the story ends, George R. R. Martin has already revealed the basic plot outline to the creators David Benioff and D. B. Weiss and who ends of on the Iron Throne. He did this in case something prevents him from finishing the novels so that fans would still be able to get their ending.
They Also Had To Guess Jon Snow’s Parents To Make The Show
In order to convince George R. R. Martin that they were passionate about the franchise and were suitable to create the show, they were posed a challenge by the author. They had to guess the true parentage of Jon Snow, which they apparently did, sparking more rumors about the R+L=J fan theory.