Everything ends and it's always sad. But everything begins again too and that's always happy." These words, spoken by Peter Capaldi during last year’s Christmas special, sum up how Doctor Who fans feel when the coveted sonic screwdriver is passed from one star to the next.

Viewers will experience both sides of the emotional coin on Christmas Day, which sees Capaldi’s last bow as the Twelfth Doctor and his regeneration into the character’s next – and first ever female – incarnation: Broadchurch actress Jodie Whittaker as the Thirteenth Doctor.

The Christmas special, titled “Twice Upon A Time”, finds our wounded hero refusing to regenerate as he stumbles around the South Pole, encountering old friends and foes. It’s a fitting end for Capaldi’s portrayal of the renegade Timelord: difficult, wilful, refusing to take the easy path.

Capaldi’s Doctor divided viewers, alienating almost as many as he won over. Cast at 55, he was the oldest Doctor since original star William Hartnell – and became the moodiest incarnation in recent history. Showrunner and “Whopremo” Steven Moffat – who departs alongside Capaldi – believed an older actor would work best following Matt Smith, the youngest ever Doctor, to provide a dramatic change and prevent constant comparisons.