David Tennant's tenure as the Doctor — he's the tenth actor to play the character — is coming to an end, which made his appearance at Comic-Con bittersweet.

There are four hours of Tennant as Doctor Who yet to broadcast in North America. "Planet of the Dead" is the first one-hour special and airs on BBC America tonight.

Taking to the stage were David Tennant, Russell Davies, exec producer and the man tasked with bringing Doctor Who back to air in 2005, Julie Gardner, exec producer and former head of BBC Wales who headed up the revival, and director Euros Lyn.

First to speak was Gardner, who said she was starting with the bad news. "We are not making any announcements about a Doctor Who movie," she said. But she did ask if a film would be something the audience would want to see. Needless to say, that suggestion was greeted with thunderous applause.

For his part, Davies said he was "gobsmacked"  by the support for his revival. "It's demystifiyng and amazing and completely brilliant and thank you."

The event included a screening of a trailer for the two-hour finale starring Tennant. which will be split over Christmas Day 2009 and New Year's Day 2010. Among the actors returning to appear in that episode are Catherine Tate (Donna Noble), John Barrowman (Captain Jack Harkness) and John Simm as The Master.

There were the expected questions about why Tennant, who has clearly enjoyed playing the role, could leave it, but Tennant was insistent that the character, and the show, were bigger than him.

"I remember when Tom Baker left and I couldn't conceive of what it would be like when he was gone," said Tennant, "but then Peter Davison came along and within three weeks I thought he was the best. Hopefully, you'll come on the journey with us and cry with us and then a few weeks later you'll think Matt Smith is the greatest."

But everyone admitted that there have been tears on the set. Gardner said that the crew were very moved as production came to a close. "Every day we were saying goodbye to someone."

Tennant professed his belief that change is part of the show. "I'm very proud to be part of the history but I'm also proud that we're handing it off and that it carries on."