In case you hadn't heard, Dr Who's big 50th anniversary show is on the way this weekend.
The Day of the Doctor stars Matt Smith (of course) as well as David Tennant and will be broadcast in 3D on BBC One on 23 November.
Described as the Doctors' "greatest adventure yet", the episode will show the Doctor's own dangerous past coming back to haunt him.
There's been a lot of talk about what to expect from the special episode. We've taken a sneaky peak behind the scenes in the clip above.