10 Things We Know So Far About the 'Doctor Who' 50th Anniversary Special

Yahoo TV

BBC America has released a set of first look photos from the upcoming "Doctor Who" 50th-anniversary special, and while the pics serve as a reminder of just how much Whovians are looking forward to the big event, they don't provide many clues to what will happen in the special.

But the gathering of multiple Whos in one episode is certainly cause for celebration, so here are 10 fun things we know for sure about the special:

1. The 75-minute episode is called "The Day of the Doctor," and it will air worldwide on Nov. 23. The simulcast — in which the special will air in 75 countries — was planned by BBC so that "Doctor Who" fans don't have to worry about the storylines being spoiled by viewers in other parts of the world. In the United States, the special will air on BBC America.

[Related: The 11 'Doctor Who' Stars: A Who's Who of Whos]

2. The special will feature two Doctor Whos, possibly three: the current doctor, Matt Smith; his predecessor, David Tennant; and John Hurt, who may or may not be some version of the doctor.

3. BBC America has confirmed that both Smith and Tennant are playing Doctor Who in the special, but Hurt — whose character was introduced to viewers in the Season 7 finale last May — might be a past version of Who, a future version of Who, an alt version of Who, a version who bridges two other versions, or not a Who at all.

4. "The Day of the Doctor" will be the penultimate appearance by Smith as the doctor. He bows out of the series in the annual Christmas special, as Scottish actor Peter Capaldi takes over and becomes the 12th Who.

[Related: 5 Reasons Why We'll Miss Matt Smith as 'Doctor Who']

5. One of the photos released by BBC America shows Smith hanging from the bottom of the TARDIS over Trafalgar Square, while in others, Tennant and Hurt are both seen, separately, at the TARDIS controls. Little else is known about the plot of the special.

6. "The Day of the Doctor" will also include the doctor's current companion, Clara Oswald, played by Jenna Coleman...

7. ...as well as his former companion, Rose Tyler, played by Billie Piper.

8. Jemma Redgrave will also reprise her role as Kate Stewart, the head of research at UNIT (the military org that combats alien threats to Earth). Stewart was introduced into the Who-verse in "Downtime," a 1995 DVD special, and she reappeared in Season 7's "The Power of Three" episode.

9. "The Day of the Doctor" is scheduled to be shown in 3D in select American movie theaters, but no details have been announced yet.

[Related: More 'Doctor Who' Photos]

10. The series' 50th anniversary will be officially celebrated by British royalty at Buckingham Palace. "Doctor Who" cast and crew members from the past and present are expected to attend the 50th-anniversary celebration hosted by the Countess of Wessex on Nov. 18, just days before the anniversary special airs. Another possible attendee of the "Who" soiree: Prince Charles, who's such a fan of the classic series that he's developed an impression of the Daleks' famous line — "Exterminate!" — that so impressed showrunner Steven Moffat that he offered the prince a guest gig on "Doctor Who."

"The Day of the Doctor" airs Nov. 23 on BBC America. Check your local listings.