While some have been relatively hard to confirm and others might need a pinch of salt, there's others that have been verified either through photographic evidence or - in this case - the word of actual actors on the series themselves.
According to a report by Empire Magazine in their latest issue, Isaac Hampstead-Wright - better known as Bran Stark - let slip Jon Snow's real name, or probably the name he'll be operating under in the new season.
You're wondering why they'd change his name, right?
Anyway, long story short, Jon Snow was revealed as the son of Rhaegar Targaryen and Lyanna Stark to screams around the world of "I KNEW IT", which opens up a whole world of possibilities for next season.
If that name sounds familiar, it's because King Jaeharys was a Targaryen king who held the throne for 55 years whilst the more recent Jaeharys was the grandfather of Daenarys Targaryen.