The Waters of Mars will close on Sunday night with a trailer for the Christmas Doctor Who – the first unnamed part of the two part Tenth Doctor finale story will feature something quite brilliant, if Rusell T Davies words in Doctor Who Magazine 415 are anything to go by…

“The final casting for David Tennant’s swansong took place in the last ADR session in October, when a wonderful and distinguished guest name joined the cast list, as a voice artist for one of our aliens.

“It’s an actor with a mighty list of credits, including many Hollywood films.”

Bearing in mind Claire Bloom and Timothy Dalton have already recorded in front of the cameras for these momentous episodes, the task remains to spend most of the weekend deciding if it’s James Earl Jones, Tom Hanks or David Bowie who will be lending their voice to this mysterious alien…