Back in the show-running driving seat for Doctor Who, Russell T. Davies is both looking to the future (by castingSex Education's Ncuti Gatwa as the new Doctor), and now digging into his past with the show by bringing back his most popular leading man and one of the best companions. David Tennant and Catherine Tate are coming back to guest star.
Tennant, of course, was the 10th Doctor, who took over the role from Christopher Eccleston and quickly became one of the Who audience's favourite people to fly the TARDIS. He starred in the show between 2005 and 2010.
Tate, meanwhile, was Donna Noble, an enthusiastic woman whose life wasn't always going quite the way she wanted it, and who was forever changed by her experiences with the Time Lord (not that she can always remember them).
So how do they come back? Davies is being mysterious for now. "Maybe this is a missing story. Or a parallel world. Or a dream, or a trick, or a flashback. The only thing I can confirm is that it's going to be spectacular, as two of our greatest stars reunite for the battle of a lifetime."
However it happens, their scenes will be shown as part of the show's 60th anniversary, which falls next year.