Doctor Who's Twelve and the Master will rekindle their...friendship...during season 9.

'Doctor Who' Season 9: New Monster To Deal With Odin & Maisie Williams? PHOTO For Episodes 5 & 6

The two Time Lords have left death and carnage in their wakes - often thanks to the Master's (Michelle Gomez) diabolical schemes - but the Tenth Doctor (David Tennant) reminded viewers how much he would hate to see his foil die. Now, showrunner Steven Moffat will harkens back to classic Who to bring about a renewed (and dysfunctional) friendship between the two.

"I was looking back at the old Jon Pertwee/Roger Delgado ones and what's fascinating about that is that they only ever play it as friends," Moffat informed Digital Spy. "They never, ever play it as enemies at all. They're just two gentlemen having fun with each other. The Doctor's best friend is a murdering psychopath, that's actually quite fun."

'Doctor Who' Season 9: Ten Years On, Why Did Christopher Eccleston Leave? Actor Speaks Out

So, what does this new revelation hold for season 9? The Mistress is slatted for a season premiere appearance which means viewers won't have to wait long to see the pair become chummy - in the way that oil mixes oh so well with water.

Find out more when Doctor Who returns to the BBC and BBC America this fall. Click the video below to see a clip from the season 8 finale.

Tags: Doctor Who television BBC BBC America