The BBC has announced a raft of programmes to mark the 50th anniversary of the first episode of Doctor Who.
A 75-minute special episode called The Day Of The Doctor will star the soon-to-leave Matt Smith and David Tennant.
Smith said: "Hope you all enjoy. There's lots more coming your way."
Other highlights include a BBC Two lecture by Professor Brian Cox on the science behind the hit show and the drama An Adventure In Space and Time, written by Mark Gatiss.
The one-off programme stars David Bradley - known to millions for his role as Filch in the Harry Potter films - as William Hartnell, who played the first Doctor in 1963.
BBC Four will introduce new audiences to Hartnell, with a re-run of the first ever story. The four episodes are being shown in a restored format, not previously broadcast in the UK.
BBC Two's flagship arts programme The Culture Show is to present Me, You and Doctor Who, with lifelong fan Matthew Sweet exploring the cultural significance of the BBC's longest running TV drama.
A 90-minute documentary on BBC Radio 2 will ask "Who Is The Doctor?" - using newly-recorded interviews and exclusive archive material to find an answer.