Russell T Davies has revealed Neil Patrick Harris was completely unaware of Doctor Who when he was offered a part on the show. The How I Met Your Mother actor is set to guest star on the long-running science-fiction programme for an upcoming 60th anniversary special episode, The Giggle. Doctor Who showrunner Russell T Davies remarked to Entertainment Weekly on Thursday: "He'd never heard of it in his life, bless him.I was lucky enough to work with the great man on a show called It's a Sin, about the AIDS crisis in the 1980s,...