Bathgate-born Tennant, 51, first stepped into the Tardis in 2005 to play the 10th Time Lord with his final episode airing on New Year’s Day in 2010, with comedic actress Tate, 52, starring as companion Donna Noble.
The duo have reunited to film scenes that are due to air next year to coincide with the 60th anniversary celebrations of the popular TV series.
Doctor Who’s returning showrunner Russell T Davies said: “They’re back! And it looks impossible – first, we announce a new Doctor, and then an old Doctor, along with the wonderful Donna, what on earth is happening?
“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.”
Tennant took over the starring role in 2005 from Christopher Eccleston and was succeeded by Matt Smith while Billie Piper’s companion role was the first in the programme’s 2005 revival and was followed by Tate as Donna.
Opinionated Donna helped to save civilisation from the Daleks during her spell with the 10th Doctor but she had her memories of her adventures in the Tardis wiped, because the powers the Time Lord had given her threatened to overwhelm her brain.
Tennant was also seen in the 50th anniversary special, The Day Of The Doctor, in 2013.
It was recently announced that Edinburgh-raised Sex Education star Ncuti Gatwa will be taking over from Jodie Whittaker to become the show’s 14th Doctor.
The 29-year-old becomes the fourth Scot to take up the post, following on from Sylvester McCoy, fellow Royal Conservatoire graduate Tennant and Peter Capaldi.
A synopsis teasing Tennant and Tate’s Doctor Who return mentioned Donna’s memory wipe to save her life, adding that the Doctor had “left her family with a warning: if ever she remembers, she will die”.
It adds: “But with the two coming face to face once more, the big question is, just what brings the Doctor and Donna back together?”.