Everyone is just catching their breath after the big Doctor Who 50th Anniversary celebrations, but the BBC remind us that there is more to come. On Christmas Day the annual, now-traditional special episode will air and this one will be dramatically more special than the previous years.

“The Time of the Doctor” as it is now titled will see current Doctor Matt Smith saying goodbye to the role he has occupied since the first day of 2010. As the episode closes we will see the eleventh (Twelfth? Thirteenth?) Doctor regenerate yet again and Peter Capaldi will assume the part.

Recent interviews with showrunner Steven Moffat seem to hint that the previously established twelve regeneration limit will come to head as we now know that there was a previously unknown regeneration in the form of John Hurt’s “War Doctor” and it appear that the “diverted regeneration energy” brouhaha from 2008’s “Journey’s End” still decreases the count by one.

However it plays out, we only have a few short weeks until “The Time of the Doctor” and the answers to some long-standing questions. In the meantime, check out the trailer below and look for all the hidden Easter Eggs in the official poster above.

Neil Gaiman is a geek god. He’s the author of several award winning books and comics including the series The Sandman and novel American Gods. He’s a Doctor Who fan and if he could’ve traveled with any incarnation of the Doctor, it would’ve been Patrick Troughton’s Second Doctor.

“Doctor Who was the first mythology that I ever knew,” he said.

Tonight Gaiman returns with Nightmare in Silver, the second episode he’s penned for the BBC America show about all of time and space. In Nightmare, the Doctor, Clara (Jenna Louise-Coleman), Artie and Angie arrive at Hedgewick’s World of Worlds, once the greatest theme park in the galaxy but now home to strange creatures and a terrifying new breed of Cybermen.

The Cybermen are not only one of the Doctor’s greatest enemies but one of Gaiman’s greatest passions. His first Doctor Who experience was seeing the fourth season episode, Moonbase, as a child. Swift and silent Cybermen were at the center of the episode and those villains stuck with Gaiman.