Hidden places inside Destiny is nothing new, and Destiny The Taken King is no different. In fact, some of the players have already found a secret room.
Apparently, the secret room that Destiny The Taken King players have found comes up in the area after the fight with Gorgoroth. In the jumping puzzles that follow, there are some platforms with lamps that take you to the room if you jump on them in a given sequence.
It is hard to explain here, so we will leave you with the video that The Taken King player has shared showcasing the secret room.