50. The Twelfth Doctor's Unheralded Debut
From: "The Day of the Doctor"
Premiere: November 23, 2013
Tucked into Eleventh Doctor Matt Smith's penultimate episode was a choice Easter egg that defied leaks and spoilers. Aiming to save the Time Lord home world Gallifrey rather than see it burn, all of the Doctor's incarnations team up: Doctors 1 through 11, plus John Hurt's War Doctor – and, seen only in a glimpse of furrowed eyebrows, the then-newly announced Twelfth Doctor, Peter Capaldi.