http://www.youtube.com/watch?v=L-cZI8VQwU4
Only four minutes and it doesn't give too many secrets away but its certainly an entertaining enough sequence shot at a Cardiff promotional show by undoubted 'a very cheeky monkey with a camera' three weeks before it is officially due to be shown.
IMO pretty good sequence!
...also on the same subject the official 'BBC Press Office' word on 'The Runaway Bride' reads as follows:-
Award-winning comedy actress Catherine Tate and Sarah Parish star alongside David Tennant in a special Christmas edition of the time-travelling adventure.
Bride-to-be Donna mysteriously vanishes as she prepares to marry her boyfriend Lance in a glittering ceremony on Christmas Eve. She suddenly appears, to her complete astonishment, in the Tardis with the Doctor.
As the Tardis races to get to the church on time, the Doctor and Donna are closely watched by the sinister figure of The Empress of Racnoss from her throne in her spaceship. It soon becomes clear that Donna is the key to an ancient alien plan to destroy the Earth.
David Tennant plays the Doctor, Catherine Tate plays Donna and Sarah Parish plays The Empress of Racnoss.

