Doctor Who star Peter Capaldi has said the Time Lord is not to be trusted – because of his alien nature.

The actor, who plays the current Doctor, teased details of the series’ return to TV screens this autumn.

A shot from the first episode of the new series
A shot from the first episode of the new series (David Venni/BBC)

He told Digital Spy: “You must never trust the Doctor, because his knowledge of the past and the future is comprehensive and deep and not quite human.

“So, in his human form, I think he’s decided – because he knows how dark it can get outside – that he’s going to have a good time.

“But as always in Doctor Who, no good time goes unpunished,” he warned.

He told Digital Spy that he’ll be lightening up his portrayal of the Time Lord in the next series.

His portrayal of a more severe and terse Doctor after his regeneration was a deliberate shift from the previous one, played by Matt Smith, the 57-year-old confirmed.

“Everyone felt it was very important to make a very decisive change,” he said.

Peter Capaldi chair on Doctor Who set
(BBC)

“I think it always happens in the first season of a new Doctor – you make a very decisive change, a contrast to who’s gone before. With Matt being so friendly and affectionate and open, I think they wanted to be quite different to that.”

But the Doctor’s companion Clara (Jenna Coleman) was able to get past his terseness, and she’ll continue to assist the Doctor this series.

“She helps the Doctor relate more effectively with human beings, because he can’t be a**ed to give them the time of day if they’re not doing what he wants!” Capaldi said. “So she helps him – she has little strategies to help him be better.”

Doctor Who returns to BBC One on Saturday, September 19.