The moment we've all been waiting for finally took place on the Game of Thrones finale. After six seasons, many theories, and one long walk up to the Tower of Joy later, Ned Stark finally made it into the Tower of Joy and found Lyanna, with baby. There, she asked him to promise something to her, after whispering a secret in his ear. So, what did Lyanna whisper to Ned Stark on Game of Thrones? Well, this moment is something that fans everywhere have been waiting for.
There's been a long-awaited theory on Game of Thrones that was confirmed — for the most part — on the Season 6 finale. That theory is that Lyanna Stark's son (Jon Snow) is not the son of Eddard Stark. Instead, the theory is that he is the son of Rhaegar Targaryen, meaning he's a Targaryen. The two (Lyanna and Rhaegar) were in the Tower of Joy together during the rebellion, which could certainly suggest that Rhaegar is the father of the baby. Plus, with Lyanna begging Ned to promise her that he'll take care of Jon... basically, this is a huge deal.
So, what was all the whispering about? Lyanna probably whispered Rhaegar's name to Ned, which at least officially confirms the theory. The even better news is, Bran was there for the whisper reveal, meaning he knows what she said, too. Why is that so important? Because Bran can finally go make himself useful and spread the word about this — or maybe keep it to himself, since he has no idea what is going on at home right now.
So, will Bran tell Jon what he knows? How will this change Jon's new post as King in the North? That whisper is very important to the rest of the show (two seasons left, but not a lot of episodes remaining). Hopefully the news spreads like wildfire — ahem — and those that are Targs (even those who don't know it yet) find peace with their identity. Yeah, right.