The pair unpack "Joy to the World," including the cultural reference they couldn't ignore. "It's a piece of our history now," says Moffat.

The TARDIS is as much a part of Christmas as turkey, mince pies, and mulled wine, and former "Doctor Who" showrunner Steven Moffat certainly knows his way around a festive adventure. This year's holiday offering,

Filming that scene in the room that’s from millions of years ago was Coughlan’s favorite, she tells TV Insider. “It had a little bit of everything. You got that emotional moment and then you have the dinosaur and the escape, and I loved all of that,” she shares. “It’s such a fond memory.”

Doctor Who is back with high-energy, heartfelt festive special “Joy to the World”. Being a Steven Moffat joint, it’s full of wild and inventive concepts, from time travelling hotel rooms to psychic briefcases, via bootstrap paradoxes and sentient stars.

Doctor Who Christmas special "Joy to the World" writer Steven Moffat and showrunner Russell T Davies dish on spoilers and script changes.

It’s Christmas Day and for fans of Doctor Who that can only mean one thing: it’s time for the yearly Christmas special! This year’s special is titled Joy to the World and will once again star Ncuti Gatwa as the Fifteenth Doctor;

With verve, imagination and fun concepts, Steven Moffat's latest Who episode wraps up Christmas in a big sentimental bow. Spoilers ahead.