'Death in Heaven' - which follows 'Dark Water' - will run for 60 minutes, it has been confirmed, reported Digital Spy.
The episode, written by Steven Moffat and directed by Rachel Talalay, will air on BBC One on November 8.
"With Cybermen on the streets of London, old friends unite against old enemies and the Doctor takes to the air in a startling new role.
"Can the mighty UNIT contain Missy? As the Doctor faces his greatest challenge, sacrifices must be made before the day is won," the synopsis of the episode read.