I don’t know whether the network meant to do so, or if they jumped the gun on this, but it appears that HBO has confirmed what we all knew to be true: The R+L=J theory is no longer theory. It is fact, at least according to HBO’s official Game of Thrones blog, Making Game of Thrones.
In trying to assist us in keeping all the relationships on the series together in the wake of Bran’s vision of Lyanna Stark’s talking about Jon Snow’s parentage with Ned Stark, the network helpfully put together an infographic that is a jumbled mess of lines and arrows that’s impossible to read unless you know what you’re looking for. The important thing, however, is that the parent lines clearly connect Jon Snow to Lyanna Stark and Rhaegar Targaryen.
(Click to embiggen)
It wasn’t exactly a secret, but the show itself did not reveal it, so it is odd that the network graphics department would confirm it, but there you go: The series worst kept secret is no longer a secret.