The BBC today opened door number twenty-seven on their online Doctor Who Advent calendar, available exclusively on the official Doctor Who website. The calendar was originally intended to run until Christmas Day, but it was recently confirmed that it would run until New Year's Day to count down to David Tennant's final episode as The Doctor, The End of Time part two. Inside today's door is a video featuring Bernard Cribbins, who features in both parts of The End of Time, singing a festive song. The video can be seen inside the twenty-seventh door on the official Doctor Who website's Advent calendar by clicking here. Door number twenty-eighth, featuring another festive surprise, will be made available to open from tomorrow, and some details regarding that will be posted here, on The Gallifrey Vortex, when the door is openable. What do you think of this Advent surprise?