Just what kind of surprises await us in this year's Doctor Who Christmas Special? According to a new interview with writer and producer Russell T. Davies, more than you may think. Including more Doctors...

Speaking on BBC Radio 5 after the first press screening of "The Next Doctor" - which Davies described as "nice and scary, but healthily scary" - the producer hinted that fans may get to see more than just Davids Morrissey and Tennant strut their Timelord stuff in the new special:

It's not just the next Doctor you get to see, you get to see some old ones as well, which is rather exciting... It's a Doctorfest.

One Doctor that we definitely won't see is David Tennant's 2010 replacement, as - if he's not just playing dumb - Davies doesn't know who that'll be:

Steven Moffat and the series 5 team are casting the next Doctor, the eleventh Doctor and it's literally nothing to do with me. Everyone keeps asking me, begging me, the money I could make out of this, but I do not know what they are planning.

One actor who definitely won't be picking up the sonic screwdriver is Robert Carlysle, whose signing up for Stargate: Universe lead to this offhand remark that makes us prepare to miss Davies all the more:

Stargate, can you believe it? That was a surprise. Hasn't his agent watched it?

"The Next Doctor" is broadcast in the UK on December 25th.

Russell T Davies and the Next Doctor [BBC]

Send an email to Graeme McMillan, the author of this post, at graeme@io9.com.