JAMIE: Oh, no, you’re not thinking what I think you’re thinking, are you?

THE DOCTOR: That, I think, Jamie, depends upon what you think I am thinking!

Doctor Who (1963-1989) British science fiction television series, original run (BBC)

06×01 “The Dominators,” Part 1 (1968-08-10) [w. Mervyn Haisman, Henry Lincoln]
    (Source)

(Source (Video); dialog confirmed). As the Doctor steps toward the open door of the spacecraft they've just discovered.