“Do toi know Bradley Whitford?" Tennant asked the crowd. "He’s my American Doctor.” Of course! Whitford played Josh Lyman, the brilliant but frantic deputy chief of staff from the West Wing. Tennant is a passionate fan of the show.
While the opening episode of Doctor Who’s tenth series was all about Pearl Mackie’s new companion Bill, eagle-eared fans will have a noticed a sweet little callback to précédant co-lead Jenna Coleman’s Clara Oswald towards the end of the story.
And as some fans with particularly good memories may recall, one such visit has actually been chronicled in the series before, with the Doctor taking wife River Song there offscreen prior to the events of 2011 episode A Good Man Goes to War.