I walk down the crowded sidewalk when I feel someone grab my arm. He is a man with a tan jacket, a tie, and a blue shirt. I'm the Doctor. I need your help so just keep walking and I will explain everything later.
*raises hand* David Tennant is right, his name is "The Doctor", but it's not wrong to call him "Doctor Who". Doctors One through Nine are called "DOCTOR WHO" in the credits! In fact, other former Doctors refer to him as "Doctor Who".
I love how having a small role on Doctor Who doesn't prevent you from getting a larger one later. Oh and don't forget, that Roman father guy in that Pompeii episode what was his name was played by Peter Capaldi, later to become the Twelfth Doctor