There are no two ways about it: it’s a great time to be a fan of the “Who”-niverse. Not only did the awesome “Torchwood: Children of Earth” miniseries blow away BBC America ratings records, thereby almost certainly insuring that we will see more of Captain Jack and company in the future, but we’ve just been witness to another great “Doctor Who” saga (“Planet of the Dead”) and will have two more coming up in the next few months, with “The Waters of Mars” premiering in the fall and the inevitable Christmas episode arriving…well, you know, somewhere around Christmas, probably. In fact, there’s really only one thing to be sad about: the imminent departure of The Tenth Doctor, otherwise known as David Tennant.

Oh, dear, I’m already starting to get sad about it. Let’s switch gears, then, and talk about how Tennant came to be The Doctor in the first place.

“I first met David when we did ‘Casanova’ together for the BBC,” said “Who” reinvigorator Russell T. Davies. “I remember doing rehearsals, and we used to make ‘Doctor Who’ jokes, which amused us. So he was already there in a way. When you work with these great actors, when you find a great actor, you just cling to them. They’re just so limitless and inspiring. So when it came to putting it together and writing it, we talked surprisingly little about it, really, didn’t we?”

“You just wrote it,” confirmed Tennant. “That was it, really. I just got the script and did it.”

So what was Tennant doing that was different from the other actors who were under consideration?

“He’s a great kisser,” replied Davies, before getting serious. “Actually, I’ll tell you what: it was the ‘Casanova’ audition, because that’s when I sort of thought, ‘Oh, my lord, that’s someone I want to spend many years working with.’ He had auditioned for ‘Casanova,’ and, you know, playing the world’s greatest lover, everyone came in and gave us very heavy and very serious would-be romantic portrayals. And David could just dance over dialogue like…”

At this point, Davies turned and addressed David directly. “I think you’re one of the few actors who understands that dialogue is sort of irrelevant,” he said. “You throw it away and you rattle across it with real speed, and it’s all going on underneath. You get the humor and the comedy, and there’s not many actors who do that. They take it very seriously. And I like stuff on the lighter end, no matter how dark the actual stuff is. It has that throw-away quality to it, and I love that.”

There was a bit more talk about the early days of Tennant’s reign as The Doctor, but it wasn’t long before we got down to brass tacks and began to ask about the impending end of said reign. Davies and Tennant then proceeded to offer up some clips of the two upcoming specials, and I’m led to understand that they were absolutely fantastic and only served to make the “Who” fans in the audience drool with anticipation.

Too bad I wasn’t there.

I had a good excuse – I had to run out to do a one-on-one with Lucy Lawless – but, damn, I still wish I’d seen them. At least I got the transcript, though, so I was able to find out what Davies had to say about how The Tenth Doctor will be reacting to the knowledge that his next incarnation is just around the corner.

“I think this doctor likes being this doctor,” said Davies. “You see it there: he’s raging against the dying of the light. And I think that’s kind of the beat that we play, don’t we? That’s the story. He knows that the sands of time are running out. He’s been told. And the bell is tolling for him, and he doesn’t want to go quietly. So I think that’s how we play that.

Davies describes “The Waters of Mars” as “one of those claustrophobic submarine-type dramas, all trapped in an enclosed space with sort of increasing darkness and intensity. It all takes place in a very small location in ‘Doctor Who’ terms.” Tennant adds that, beginning with this special, “the sword of Damocles is dangling, I think, and that informs everything that goes on.”

It’s a situation which continues into the subsequent Christmas specials, according to Tennant. “You go into the finale,” says Davies, “and that’s sort of a personal epic. That final story, it becomes, yes, epic. Almost like a fairytale. But in that there’s, like, a seven-minute scene of David and Bernard Cribbins having a conversation together in a cafe, it’s really intimate at the same time.”

The experience of doing these final specials has a bit emotional for Tennant, who cops to a certain number of tears on the set during the course of the 2-part Christmas episode, but each has been a bit different in its own way.

“Planet of the Dead” – “We had Michelle Ryan, who, to all intents and purposes, was the companion, and she’s fantastic, although she was a very distinct character. She’s kind of in the mold of the traditional, you know, young, beautiful woman, sort of feisty.

“Waters of Mars” – “The closer thing we have to a companion is Lindsey Duncan, who is an older woman, which is not something the show has done before. And she probably thinks she’s more in charge than the doctor is. In many ways, she is, actually. So that’s a different dynamic

2009 Christmas special – “Although Catherine Tate is back and Donna is a big part of that story, really, the companion is Bernard Cribbins, the first time the doctor has had an 80-year-old man as his sidekick, really.”

“It’s been great to get to play these different facets of the character, I suppose,” said Tennant. “And The Doctor himself is also slightly on the run from himself and on the run from the inevitable. He’s trying not to get too close to anyone, so it’s important that there’s kind of a revolving door of confidence for him, but getting to see Bernard Cribbins as well in that final story is so brilliant and moving. He’s just such a great actor that that was a great finish to the story for me. And as Russ was saying earlier, what you get is these wonderful scenes of these two old men. The doctor is a lot older than Wilf, and yet the two of them get to sit down and discuss life in a way that we’ve never seen the doctor be able to do before. So it’s just a way of reinventing the wheel, I suppose, with this character who has been around since 1963, and yet we are still managing to find a new aspect of him, I think.”

You are, indeed.

Just one more before we go: what are the odds of seeing the Tenth Doctor return at some point in the future? Is that something you’ll be willing to consider?

“I’ll wait for the correct opportunity, but I’ve got the costume hanging up in my wardrobe,” said Tennant, with a grin. “As long as I can keep my waistline and still fit into the trousers, never say never!”