Filming on the show, which will also star John Hurt ( Alien , The Elephant Man , general legend), will start next week.
Tennant and Piper have long been rumoured to be making a return for the special, which is being written by the show's executive producer and lead writer Steven Moffat.
But has anyone managed to tempt Christopher Eccleston back?
Earlier this week John Barrowman tweeted that Captain Jack would not be in the special.
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