Film: 11 Harrowhouse (1974) [Aram Avakian, Dir.]

Rainy day in the ol' Pueblo and there is no better matinee, than a heist matinee. Cast of 70s awesomeness includes Charles Grodin (thoroughly unimpressed by anyone, including himself), Candice Bergen (never hotter or more fun), James Mason (mellow and superior in all ways) and dastardly Brits Trevor Howard and John Gielgud.

Creme de menthe is the diamond dealer's drink of choice.

Diamonds, roaches (key to the climax!), roof top acrobatics and a car chase across a sprawling English estate---11 Harrowhouse is a winkingdelight. A legit post-modern diamond heist, with a babe as our action jackson and an anti-hero confronting the international diamond industry.

70s era second wave feminism influences the love story as playful and flippant with Bergen's character, Maren Shirell the ace and foil to Grodin's general schlemiel-esque hero (whose noncommittal voiceover masterminds the heist). Grodin is H.R. Chesser, a small time diamond dealer, who takes on the premiere London diamond house, with the aid of James Mason's Charles Watts, a diamond expert with a secret of his own..

A strategy based on the chocolate cake principle?

A Burberry and bowler meeting.

Chesser: "And I bought this terrific outfit and everything."

Trailer

IMDB

Note: Obviously Grodin cut his chops on 11 Harrowhouse before starring in the greatest diamond heist of all time, The Great Muppet Caper.