Apologies if this has already been mentioned, but if not I thought you might be interested to see this special scene written by Russell T Davies.
It appeared on John Barrowman's entertainment show over here called Tonight's The Night, and shows a DW fan who won the shows competition to create an alien, where the prize was to star in the special scene.
Look out for a special guest.
https://www.youtube.com/watch?v=tgg0Ul0aus4