http://scifipulse.net/Dr_Who/Dr_Who_Series4_Shooting_Begins.html
BIG VERSION-
http://www.bbc.co.uk/doctorwho/gallery/doctor_donna/800/21.jpg official BBC report-
http://www.bbc.co.uk/doctorwho/news/cult/news/drwho/2007/08/10/47771.shtml Doctor Who’s executive producer and head writer, Russell T Davies comments: "Visiting Agatha Christie has been on my wish-list for ages now, and for the Doctor, it's a real meeting of minds! Viewers can expect many more ambitious storylines and a whole host of guest stars in 2008."
Mathew Prichard, Agatha Christie’s grandson comments,
"What a brilliant idea that Agatha Christie and ‘Doctor Who’ should meet! Two characters whose contribution to British entertainment is absolutely unrivalled. As far as I know my grandmother, Agatha Christie, never saw Doctor Who, but I am sure she would have been intrigued, excited and above all flattered by all this attention in 2007."
Catherine Tate said: "I am delighted to be returning to Doctor Who. I had a blast last Christmas and look forward to travelling again through time and space with that nice man from Gallifrey."
i assume this is the gareth roberts penned episode