This video was uploaded to Youtube back in November, but I only just heard about it the other day. The "Thomas" in question is a nine-year-old autistic boy who loves Doctor Who. His grandmother had recently died, leaving the boy grief-stricken. Peter Capaldi, the actor who plays the Doctor, recorded this video message and sent it to him to cheer him up. Thomas' father uploaded it to Youtube and it quickly went viral.
Think what you like about DW, this was a classy move.