Doctor Who: new series trailer shows Peter Capaldi as a dark Doctor (Video)

The BBC have released an electrifying teaser trailer to promote the eighth series of Doctor Who, in which Peter Capaldi debuts as the 12th Time Lord, with Jenna Coleman as his companion Clara.

And Clara looks very worried…

“Clara, be my pal. Tell me: am I a good man?” says the Doctor.

But Clara can’t.

“I don’t think I know who the Doctor is any more,” she says.

The new Doctor Who series begins on BBC1, on Saturday, August 23.