The Twelfth Doctor and Clara Oswald will need to redefine their relationship after the Time Lords' latest regeneration on Doctor Who.

'Doctor Who' Is 'Not A Fairytale', Consequences To Rule Twelve's Run

Jumping from Matt Smith's friendly and dependable Eleven to Peter Capaldi's untried, seemingly dark and dangerous Twelve will be no easy transition for the young companion.

"From a Doctor she could sort of control, because he had a crush on her, she's landed with a Doctor who barely registers that she's a girl," said showrunner Steven Moffat, according to SFX. "They're great friends and all that but she has to be his human interface with everybody else."

Clara Or Twelve Won't 'Know What To Do' In The 'Doctor Who' Finale, What Problems Will They Face?

Whereas Eleven once left Clara behind in an effort to keep her safe, Twelve will be a far less thoughtful Time Lord than his predecessor. Capaldi, it seems, will be more likely to leave his companion behind just because he is rather unreliable.

"I would like to restore the sense that when he says 'Wait here, I'll be back' you really hope he'll be back, but you're not absolutely convinced," Moffat told SFX. "What he's not doing is reassuring you very much."

Do you think Twelve will eventually become someone Clara can trust and rely on? Sound off in the poll below!

Check out the newest Doctor when Doctor Who returns to the BBC and BBC America on Aug. 23.

Tags: Doctor Who television BBC BBC America