David Tennant recalls origins of the Tenth Doctor and early "scrutiny" 20 years after Doctor Who debut

It’s hard to believe it’s been 20 years since David Tennant emerged as one of the most beloved incarnations of the Doctor in the Doctor Who Christmas Special The Christmas Invasion, which aired on Christmas Day 2005.

To celebrate the milestone, Tennant joined the festive edition of the Whoniverse Show to reflect on the episode, sharing insights and memories from his first full-length appearance as the Tenth Doctor.

"People are always like, ‘Oh, how did you decide how your Doctor was going to be, how you were going to talk? Did you and Russell have long conversations? Did you sit up all night discussing the ins and outs of character choices?’" Tennant reminisced.

"And we absolutely didn’t at all. It just made sense. It didn’t feel like there were conversations to be had. I think I have spent my life watching Doctor Who and so has Russell," he added. "I think we both came from a similar place."

"I felt like I absolutely understood how he’d written it, when they’re written that well, you just need to say the words," Tennant commented. "So it was not something that ever felt mysterious to me."

Tennant had previously worked with the Doctor Who stalwart Russell T Davies on the three-part 2005 BBC drama Casanova, in which he starred as the young Giacomo Casanova. The series proved a major breakout role for the actor, with Davies shortly casting him in the iconic role of the Doctor.

Later in the episode, Davies also reflected on their time working on Casanova, admitting they "used to sit around talking about Doctor Who an awful lot."

"There was a scene with three doctors in it and we sat there going 'three doctors!'" he added. "I was showing him photos of everything that was happening [on Doctor Who]."

The Christmas Invasion featured Tennant's Doctor in his newly regenerated form for his first full-length episode, as the Gallifreyan Timelord is forced to leave Rose, Mickey and Jackie in charge of stopping the Sycorax’s invasion of Earth on Christmas Eve.

The episode proved such a success, it sparked the long-running tradition of Doctor Who Christmas specials, and is considered to be one of the most loved festive episodes - thanks in part to the deadly Christmas trees and unforgettable sword fight.

Tennant also reflected on the pressure of his first episode being a Christmas special: "You’re in everyone’s living room on Christmas Day…there was a lot of pressure and a lot of scrutiny, but also how joyous to be in the middle."

"I mean to be in the middle of Christmas Day television. In those days people got their Christmas copy of the Radio Times and you put a circle around what you were all going to watch as a family," he added. "And it felt like at that moment, watching Doctor Who as a family was kind of what everyone was doing."

"Certainly what we were doing up in Scotland. I had to sit with my family and watch it, which was thrilling and awful in equal measure!"

Doctor Who is available to watch on BBC iPlayer.

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