The trailer for series 4 of the Sarah Jane Adventures gave fans a glimpse of a possible reunion between the Doctor and his old companion Sarah Jane Smith. The Sarah Jane Adventures is a spin-off show from Doctor Who.
I would personally love to see how this story line would play out between the two shows, and how Sarah Jane will react to seeing the new Doctor, as opposed to the last time when he still was played by David Tennant. Check out the short teaser trailer below.
