The last episode of 'Doctor Who' may have been all about the Doctor, but the Series Nine finale will be bringing back some of the most popular characters in the history of the show!

In 'Heaven Sent,' the show focused on the Twelfth Doctor's anger and frustration over the death of his companion Clara Oswald (Jenna Coleman). The eleventh episode of Series Nine only featured Peter Capaldi as Twelve as well as Jami Reid-Quarrell as the Veil, although Jenna Coleman's voice was used as the Doctor's conscience. By the end of the episode, the Twelfth Doctor ends up in Gallifrey, where he announces that he is the Hybrid that is destined to conquer the planet.

'Heaven Sent' was truly a remarkable episode, but it seems like the series finale is determined to outdo its predecessor with a stunning array of returning characters, as shown in the episode trailer.

The Time Lords are back, and so are the Daleks and the terrifying fan favorites, the Weeping Angels. The General (Ken Bones) from 'The Day of the Doctor' is also coming back in the Series Nine finale.

In addition to an already stellar cast, 'Hell Bent' will mark the (hopefully not final) return of Ashildr/Me, who is played to bits by Maisie Williams. Although there have been rumors that the 'Game of Thrones' actress will be the new Companion to the Doctor, the character's role in the ninth series has proven that this is very unlikely.

But where is Clara Oswald? Will Jenna Coleman be making one last appearance before leaving 'Doctor Who' for good?

The trailer offers a hint to Clara's return in 'Hell Bent,' as a female is seen taking the Doctor's hand. Most fans believe this could be Clara Oswald coming back to say one last goodbye to Twelve.

'Hell Bent' was written by Steven Moffat and directed by Rachel Talalay. The series finale will air on December 5.