Matt Smith and David Tennant are coming together for the "Doctor Who" 50th anniversary special. The Tenth Doctor and Eleventh Doctor have already been spotted filming, but now BBC is giving fans a behind-the-scenes look with a new Smith and Tennant interview.

In the video above, Smith and Tennant discuss the joys of being the Doctor and how they interact on camera. Spoiler alert, their two Doctors bicker, but get along. Plus there's somebody amused by it all whom they cannot talk about.

Smith and Tennant will be joined by Jenna-Louise Coleman, Billie Piper, Jemma Redgrave, John Hurt and Joanna Page.

Speculate away about who the mystery person is in the comments below.

"Doctor Who" airs Saturdays, 8 p.m. ET on BBC America.

Loading Slideshow...
  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • "The Day Of The Doctor"

  • The Day of the Doctor

  • The Day of the Doctor

  • The Day of the Doctor

  • The Day of the Doctor

  • The Day of the Doctor

  • The Day of the Doctor

  • The Day of the Doctor