Okay, we should be clear on this from the off. If you like watching Doctor Who episodes and knowing nothing about them beforehand, this is not an article you want to read.

While chunks of what we're rounding up here has been mentioned before, but there are still spoilers ahead...

Still here? Then here's a digest of what's known about the Christmas specials so far...

• In The End Of Time, Russell T Davies has revealed that we're going to meet a new type of Ood (who we actually met at the end of WoM). He revealed this in the Q&A after the press screening of The Waters Of Mars. That's all he was willing to say on the matter, though.
  
• As was revealed at the end of the trailer for The End Of Time, the returning cast includes Bernard Cribbins as Wilf, Catherine Tate as Donna and Jacqueline King as Donna's mum Sylvia.
  
• We understand that Bernard Cribbins has a meatier role in the specials, too, and that he will to a point be taking the assistant role. Russell T Davies has said that in interviews.
  
• Also returning is John Simm as The Master and Alexandra Moen as his wife. The Master, as the trailer for The End Of Time has revealed, will have bleached blonde hair this time round, and will be even more manic than when we last saw him in The Last Of The Time Lords
  
• The End Of Time will also feature Jessica Hynes, returning to Doctor Who for the first time since the excellent Family Of Blood two-parter. Further familiar faces in the cast of the two episodes are Billie Piper as Rose Tyler, Tommy Knight as Luke Smith, John Barrowman as Captain Jack Harkness and - yes! - Elisabeth Sladen as Sarah Jane Smith.
  
• Timothy Dalton, contrary to some reports, is definitely in the specials too. Photos online have shown him dressed in the style of a Time Lord, but thus far you've heard him doing voiceover work on The End Of Time trail (as heard at Comic Con earlier this year)
  
• The first clip of the Christmas episode will be shown as part of the BBC Children In Need transmission this coming Friday, 20^th November. The scene is apparently around three minutes long.
  
• The second of the two episodes is reportedly weighing in at 75 minutes, the longest single episode since the show returned to our screens.
  
• The End Of Time is apparently the title of the second of the two Christmas specials. The name of the first episode has yet to be confirmed, although it will be six words long (it may yet be The End Of Time Part I, of course). The first special will be broadcast on Christmas Day, and the second is expected to be screened on New Years' Day.

We'll keep you posted with more on The End Of Time as we get it.

And in the interim, do take some time to check out the excellent Radio Free Skaro here.