David Tennant Talks 'Doctor Who' Season Finale: Time War Secrets, Familiar Faces And A 'Brilliant' Twist

"Doctor Who," the long-running BBC science-fiction series that follows a time- and space-traveling explorer known as The Doctor, concludes its current season this weekend with a two-part finale that kicks off Christmas Day, December 25. Not only does "The End of Time" finale conclude the latest season, but it will also see the departure actor David Tennant, who's played The Doctor for the last three seasons and seen the series' popularity explode to unprecedented levels here in the U.S., spawning spin-offs such as "Torchwood" and "The Sarah Jane Chronicles."

As MTV's resident "Doctor Who" geek, I jumped at the opportunity to chat with Tennant about the impending conclusion to his run as The Doctor — and what we can expect to see in the season finale.

"I can't give anything away, that would go against the grain, wouldn't it?" smiled Tennant, who went on to tease some of what we might see when "The End of Time" kicks off.

"You're going to learn a bit more about what happened during the fabled Time War," he teased. "You will see the reappearance of some familiar faces from The Doctor's past — some expected, some rather unexpected. But the stories also stand alone, really."

With the most recent episode revealing a side of The Doctor that fans might not be accustomed to, Tennant explained that the emotions his character is exploring aren't the only twists saved for the conclusion of the current season.

"It's this big bold story about this character who knows he's going to die, "explained Tennant. "It's a big, exciting story arc that takes The Doctor to places he's never been before. This show has been running since 1963, so it's quite hard to keep reinventing it, but we manage to do things to The Doctor that have never been done to him before."

"It's brilliant... and I can't wait for people to see it," he said.

"The End of Time" kicks off Friday, December 25 on BBC and BBC America.