The BBC has confirmed a slight schedule change for the third episode of the second series – School Reunion will now air at 7.20pm on Saturday.
This much anticipated episode sees The Doctor investigating a London school which is being haunted by strange, bat-like creatures at night.
While at the school the Doctor encounters former companion Sarah Jane Smith who is already working undercover.
Both have old scores they must settle, and Rose discovers the true legacy of being a Time Lord�s companion.
Also returning is K9, the Doctor’s robot dog who was sent to Earth as a gift for Sarah and who was last seen on screen in the 25th Anniversary special The Five Doctors.
David Tennant plays the Doctor, Billie Piper plays Rose, Noel Clarke plays Mickey, Elisabeth Sladen plays Sarah Jane Smith, Anthony Head plays Mr Finch and John Leeson plays K9.