David Tennant's final Doctor Who companion has been revealed, and it's a familiar face to fans of the Time Lord.
Doctor Who boss Russell T Davies has said that Bernard Cribbins - who played Donna Noble's grandad - will be back at Christmas as a companion.
Davies added that it will be a packed end to the year, with a special in November and a two-parter at Christmas.
So does that mean Donna will be back too? And if so will she still be unable to remember her adventures?
And internet rumours suggest other characters could be back too for Christmas, as the actors who play them have been spotted on the film set.
We don't want to give anything away, but it seems like the Tardis could be packed tightly before Tennant hands over the keys to a new actor.
But while those episodes are a long way off yet, there is a brand new one being shown on Saturday.
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It's called Planet of the Dead, and stars former EastEnder Michelle Ryan as a jewel thief who bumps into the Doctor and ends up travelling with him.
The Christmas specials are the last of four special episodes that will see Tennant give up the role as the Doctor.
Taking his place in the Tardis will be Matt Smith, who will become the 11th Doctor and star in his own series in 2010.