Did Matt Smith’s Final Doctor Who Episode Secretly Include River?

Although Matt Smith’s incarnation of The Doctor supposedly said goodbye to his wife River Song in “The Name of the Doctor,” one theory suggests that the character also appeared in his final ever Doctor Who episode. Smith’s tenure as The Doctor ended with “The Time of The Doctor,” which saw the titular Time Lord travel across the universe to investigate a mysterious signal that turned out to be another crack in time and space that had emerged on Trenzalore – the planet where he’s destined to die. The episode follows The Doctor as he protects the people of Trenzalore from invasion for hundreds of years.