By now we all know that Ned Stark is not Jon Snow's real father. The final episode of Game of Thrones Season 6 confirmed that his mother is Ned's sister Lyanna Stark, and then HBO accidentally revealed that his father is the late Rhaegar Targaryen - son of the Mad King and eldest brother of Daenerys. But was his name actually Jon? One Redditor doesn't think so.
If you paid attention to the scene where we find out Jon's true identity, you can't hear exactly what Lyanna tells Ned before she dies. You can just about hear her say "his name is..." but the rest is obscured. Nobody can hear everything she says (GamesRadar tried their best) but Redditor sparkledavisjr has an idea of what Lyanna said. They think Jon's real name is Jaehaerys.
Why? You might ask. Apparently Jon would have been named after Jaehaerys I and II - Jon's great-grandfather and great-great-grandfather. That's fairly important, since it would instantly make Jon recognisable as a Targaryen and not just a regular ol' bastard. It's also significant since Jaehaerys II was the person who first heard the prophecy of the Prince That Was Promised. Originally this was believed to be Rhaegar, and then his children.
Book readers will already be well aware that Rhaegar was obsessed with the prophecy, and it's been speculated that the main reason he ran away with Lyanna is because the prophecy states that "the dragon has three heads". He interpreted this to mean three siblings (like the three original Targaryens who conquered Westeros), and since his his own wife Elia Martel was unable to have a third child he had to look elsewhere. So to speak.
Even though Jon never inherited the instantly recognisable Targaryen characteristics like blonde hair and purple eyes, a name like Jaehaerys would never have gone unnoticed. Ned promised to Lyanna that he would protect Jon from Robert Baratheon (who would have had him killed at the first opportunity), so he was forced to change the name to something much less conspicuous. There aren't many names more ordinary than Jon. [Reddit via BGR]