HBO relased this week the new “Game of Thrones: Season 7 Episode 5 Preview”. You can watch it here.
Only a few minutes after the last episode finished, as every end of episodes, HBO just launched the trailer for Game of Thrones season 7 episode 5 on YouTube, and it seems King Jon has been in contact with Bran.
He only discusses what his brother told him about the Night King in the movietrailer, but it is very possible the Three-Eyed Raven had a chance to share the news of Jon’s true parentage too.
That said, with Dragonstone being a long way from Winterfell, it is likely Jon and Bran only communicated by raven, which may not be the most personal way to drop the bomb about the baby-daddy. Then again, Bran seems very much beyond giving a damn about politeness.