David Bradley and Peter Capaldi in a scene from the Christmas episode of Doctor Who.
David Bradley and Peter Capaldi in a scene from the Christmas episode of Doctor Who. Simon Ridgway

REVIEW: 'Brilliant' conclusion for 12th Doctor

"Aww brilliant.”

The first words uttered by Jodie Whittaker's 13th Doctor, the first female incarnation of the Time Lord, quite aptly sum up what was a beautiful farewell to the 12th Doctor, Peter Capaldi.

The episode begins where the series 10 final left us, with the 12th Doctor in the Antarctic bumping into his first self, played by David Bradley (William Hartnell, the actor who originated the role in the 1960s, died in the '70s).

Both Doctors are on the cusp of their respective regenerations and they have to decide whether to change into a new person, or to die.

Time is suddenly frozen when in walks a dazed and confused character known as the Captain (Mark Gattis), who moments earlier had been on a World War I battle field about to be shot by a German soldier.

The villain as such in this episode is called Testimonial, an alien being that apparently saves peoples memories once they die, projecting those memories, and thus that person, onto a glass humanoid figure. Testimonial did not mean for the Captain to survive so chases down the Doctors, companion Bill Potts (Pearl Mackie) and the Captain. Though are its intentions evil?

In some respects, this episode is a Doctor Who take on classic film It's A Wonderful Life. It's funny, it's deep, it's dark and ultimately it's about choosing to go on and continue living.

Twice Upon A Time really isn't about the alien threat, it's about connection and the importance of memory.

Those points are really brought home in the final ten minutes of the episode, where the Captain's true identity is revealed and a beautiful scene involving the Christmas Truce of 1914 is shown. Have tissues ready.

Director Rachel Talalay's directing is as beautiful to watch as ever. The episode looks absolutely stunning.

Capaldi's final moments as the 12th Doctor are fitting, he delivers one of his best monologues of his time in the show, something he has become renowned for during his time in the show.

For those wanting to see the first female Doctor in action, we just get but a short glimpse of her at the end of the episode following 12's regeneration, but what a glimpse.

Any concern a viewer might have had about Whittaker's casting is instantly washed away by the pure look of madness and joy the thirteenth Doctor displays.

It is going to be a long wait between now and Spring 2018, when Series 11 starts, but for now thank you Peter Capaldi and thank you outgoing show-runner Steven Moffat.

Twice Upon A Time is on ABC iView.