The Doctor (Doctor Who) Time Lords a fixed number of twelve regenerations, meaning that every Time Lord had a total of thirteen incarnations including the original. The plot of "The Time of the Doctor" involves the Doctor receiving a new cycle of regenerations from the Time Lords before his expected demise, triggering the regeneration into the Twelfth Doctor, played by Peter Capaldi. The origins of the programme were explored in the docudrama "An Adventure in Space and Time" as part of the 50th anniversary celebrations of "Doctor Who", which starred David Bradley as William Hartnell. Although Time Lords resemble humans, their physiology differs in
The Doctor (Doctor Who) the regions" with a Scottish one, and so asked Tennant to affect the same accent he used for the earlier BBC period drama "Casanova". In contrast, Peter Capaldi was explicitly allowed to continue using his native Scottish accent as the Twelfth Doctor. In the Big Finish audio adventure "The Sirens of Time", the captain aboard a German U-boat assumes he is English because of the way he pronounces his words: "So, you speak German ... but you speak it like an English gentleman." The Doctor's clothing has been equally distinctive, from the distinguished Edwardian suits of the First Doctor to