Content of the mildly spoil-y nature below the gif.
If you've read the books, or just really love the Song of Ice and Fire lore, you probably have already immersed yourself in the massive discussion about Jon Snow's parentage, the most popular theory being the R+L theory going back even earlier than this thread from 2006. This theory isn't new.
What is the R+L Theory?
The theory that Jon Snow's parents are actually Rhaegar Targaryen, the previous heir to the Iron Throne/the son of the Mad King, and Lyanna Stark, Eddard Stark's dead sister. Their history goes that before Game of Thrones (book/season 1), Rhaegar Targaryen crowned Lyanna Stark the Queen of Love and Beauty, instead of the princess of Dorne (his wife, Elia). He allegedly kidnapped her years later, which incited Robert's Rebellion, causing Robert Baratheon to win the throne and set the events for the series. Total possible that he could've impregnated her just before going off to war.
What Supports This?
Eddard claims that he caved and impregnated a milkmaid named Wylla while gone away from the war (explaining why Catelyn hates Jon so much), but most people have pointed out that Eddard has far too much honour ever to do that. Still, Jon undeniably looks like Eddard and Arya, so it's unlikely he's not at least half of a Stark. Arya is also said to look like a spitting image of Lyanna. Also, we know that Eddard made a "secret promise" to Lyanna (the only living person who knows this secret now being Howland Reed).
Rhaegar, Elia, and Lyanna all being dead, Eddard agreed to raise Jon.
The main implications of this theory:
- Jon is half Targaryen: if Rhaegar and Lyanna married in secret, Jon is the heir to the Iron Throne
- Jon could marry Daenerys
Personally, I've always believed in the A+E theory from 2005 that Eddard Stark really is Jon's father, and the mother is Ashara Dayne, Eddard's true love who committed suicide. I'll probably never really stop believing that theory in my heart, but Sean Bean did an AMA on Reddit. And while it was great (no, really. A lot of great things happened that night.) Nothing as great as the nerd-important revelations he revealed about Jon Snow not being Eddard's:
What do you think, is this enough confirmation that Rhaegar and Lyanna are a thing?
Okay. So it doesn't exactly confirm Rhaegar and Lyanna. But I think we can say that Jon's mother was not a milkmaid named Wylla (and probably not Ashara Dayne either ☹)