Jenna Coleman will return to "Doctor Who" for the Christmas special.
The 31-year-old actress has reportedly agreed to reprise her role as Clara Oswald -
a part she turned her back on in 2015 following three years on the show - over the festive season in order to give Peter Capaldi, who will step down as the Time Lord and hand over the reins to a new actor, the "send off he deserves".
A source told the Daily Mirror newspaper: "Jenna Coleman has agreed to film something new as Clara. It's become a tradition now for the companions to reappear as the Doctor regenerates and Jenna isn't letting the side down. It'll help to give Peter the send-off he deserves after three years."
The Christmas special will also see the return of David Bradley's First Doctor.
In a cliff-hanger ending to the series 10 finale, Capaldi's Doctor was fatally shot by a Mondasian Cyberman and begin to regenerate. Stepping out of the TARDIS into an arctic landscape, he fought off the glowing regeneration energy and fell to his knees, vowing that this time he would not live on and change into a new Doctor.
However, this was declared "ridiculous" by an approaching figure, who mocked the Doctor as he stepped forward through the snow to reveal himself as the very first incarnation of the Time Lord.
He said: "The Doctor? Oh, I don't think so. No, dear me, no. You may be a doctor, but I am the Doctor. The original, you might say."
The story is set to continue throughout the Christmas special, where Capaldi's replacement will be introduced.
This will also be the first multi-Doctor episode since 2013.
David previously played actor William Hartnell playing the First Doctor in the drama "An Adventure in Space and Time" as part of the show's 50th anniversary celebrations in 2013. Hartnell played the first incarnation of the Doctor from 1963 to 1966 but passed away in 1975.