A Hard Day's Night is a 1964 British comedy film directed by Richard Lester and starring the Beatles—John Lennon, Paul McCartney, George Harrison and Ringo Starr—during the height of Beatlemania. It was written by Alun Owen and originally released by United Artists. The film portrays several days in the lives of the group. Wikipedia
Paul: Yeah, where's the old mixer?
Grandfather: Here, Paulie.
Paul: I've got a few words to say to you, two-faced John McCartney.
John: Oh, leave him alone. He's back, isn't he? He can't help being old.
Paul: What's being old got to do with it? He's a trouble-maker and a mixer, that's good enough for me!