The festive special has already been filmed but how Bradley’s character, Graham will leave, is under lock and key.
A show source told MirrorOnline: “Two years is a long time in the world of Doctor Who. Yaz will be back but Christmas will be the last outing for Ryan and Graham.”
Bradley has now spoken out about the decision which finally made him quit the show.
He told MirrorOnline: “We have great fun doing it. But you must sleep and look after yourself because if you don’t, you will come unstuck.