Trivia: Tinker, Tailor, Soldier, Spy
- Actor Allusion: It seems that John Hurt always had a lot of experience with British political extremes and secret services.
- Dawson Casting: Karla's daughter is supposed to be in her twenties but the actress is in her thirties.
- Dyeing for Your Art:
- Oldman's hair (lighter) and waistline (heavier).
- Cumberbatch as well - Guillam's hair is blonde, while Mr. Cumberbatch is naturally a ginger.
- Hey, It's That Guy!: It's an All-Star Cast which includes Commissioner James Gordon, King George VI, The Emperor Caligula, Julius Caesar, Bane, The Dream Lord, the thoroughly modern Sherlock Holmes, his nemesis from the 2009 film version and many more!
- Playing Against Type: Colin Firth and Mark Strong co-star in a movie where one plays a kindly schoolteacher haunted by his past, and one plays a depraved turncoat spy selling international secrets to the Soviets. Sounds pretty typical, unless you know that Strong's the schoolteacher and Firth's the evil spy.
- What Could Have Been: Oldboy director Park Chan Wook was offered the film at one point.