If you've ever wondered about the origin story of "Doctor Who," wonder no longer.

BBC America announced Tuesday that it will co-produce "An Adventure in Space and Time," a scripted special that will tell the story of how the sci-fi series, which celebrates its 50th anniversary this year, came to exist.

Mark Gatiss, who has written episodes of both "Sherlock" and "Doctor Who," will write the special. "Harry Potter" actor David Bradley will portray the first Doctor, William Hartnell, and "Call the Midwife's" Jessica Raine will play producer Verity Lambert.

Brian Cox of the "Bourne" films will play the BBC's Head of Drama, Sydney Newman, who is credited with creating "Doctor Who" five decades ago. Steven Moffat -- head of all things "Doctor Who" at the moment and also a writer-producer on "Sherlock" -- will act as a producer on the "Doctor Who" special.

"Mark has written such a wonderful script not only about the birth of a cultural phenomenon, but a moment in television’s history," Bradley said in a statement from BBC America. "William Hartnell was one of the finest character actors of our time and as a fan I want to make sure that I do him justice. I’m so looking forward to getting started.”  

No air date for the special has been set (the BBC's statement only said it will arrive "later this year"), but smart betting has "An Adventure" airing in the fall, around Nov. 23 or so. "Doctor Who" debuted on the BBC on that date in 1963.

The new season of "Doctor Who," starring Matt Smith and Jenna-Louise Coleman, arrives March 30, the network recently announced.

There's still no hard information on something "Doctor Who" fans are clearly salivating for -- a special episode of the show that would reunite all the actors who have played the interstellar traveler (all those who are living, that is: Tom Baker, Peter Davison, Colin Baker, Sylvester McCoy, Paul McGann, Christopher Eccleston and David Tennant).

As we wait for that reunion special update, we'll wonder if Troy and Abed will be thrilled about today's news. Doesn't the "Doctor Who" program announced today sound a lot like "Inspector Spacetime," their favorite sci-fi show?

Loading Slideshow...
  • Madness Ends

  • Madness Ends

  • Madness Ends

  • Madness Ends

  • Continuum

  • Spilt Milk

  • Spilt Milk

  • Spilt Milk

  • Spilt Milk

  • Spilt Milk

  • Spilt Milk

  • Name Change

  • Name Change

  • Name Change

  • Name Change

  • The Coat Hanger

  • The Coat Hanger

  • The Coat Hanger

  • The Coat Hanger

  • Unholy Night

  • Unholy Night

  • Unholy Night

  • Unholy Night

  • Unholy Night

  • Dark Cousin

  • Dark Cousin

  • Dark Cousin

  • Dark Cousin

  • Dark Cousin

  • The Origins Of Monstrosity

  • The Origins Of Monstrosity

  • The Origins Of Monstrosity

  • The Origins Of Monstrosity

  • The Origins Of Monstrosity

  • I Am Anne Frank, Pt. 2

  • I Am Anne Frank, Pt. 2

  • I Am Anne Frank, Pt. 2

  • I Am Anne Frank, Pt. 2

  • I Am Anne Frank, Pt. 2

  • I Am Anne Frank, Pt. 2

  • I Am Anne Frank, Pt. 1

  • I Am Anne Frank, Pt. 1

  • I Am Anne Frank, Pt. 1

  • I Am Anne Frank, Pt. 1

  • I Am Anne Frank, Pt. 1

  • I Am Anne Frank, Pt. 1

  • Nor'easter

  • Nor'easter

  • Nor'easter

  • Nor'easter

  • Nor'easter

Also on HuffPost: