In today’s age of cell-phone cameras, Twitter spoilers, and studio hacking sagas, it takes C.I.A.-quality covert operations for a showrunner to keep his/her next episode a secret. As such, we must pay Mad Men mastermind Matthew Weiner appropriate respect for being able to keep the grand finale of his Emmy-winning AMC drama tightly guarded, even though his cast and crew filmed that closer almost a year ago. And just how was Weiner able to pull off this feat in spoiler subversion? By creating a false ending to his series.

Per GQ:

John Slattery, who plays Roger Sterling on the show, received his script for the final episode before shooting began, and read excitedly to the end. What he found there was strangely underwhelming. "I thought, 'Wait, what?' It wasn't as . . eventful as you would expect." That was the feeling at the episode's table read, attended by the entire cast and plenty of curious crew.

Alas, Weiner had a card up his sleeve.

Then, after a pause, Matthew Weiner called out a list of core cast members, most of whom had been on the show since the beginning, and asked them to follow him to his office. There he revealed the real ending. It was a level of caution that was probably warranted, considering that, thanks to AMC's decision to split the final season into two parts, the secret would have to be kept for well over a year.

Jon Hamm also deserves some kind of kudos because he managed to keep Don Draper’s fate classified for even longer. Weiner shared the ending with his Mad Men star several seasons back. And this is the only clue that Hamm could provide GQ: “[Weiner] just kind of had this idea. This image,” he told the magazine. “I said, 'That's very poetic. All right.’ ”

Although Hamm has kept that secret from most of the world, he admitted last fall that he did spoil the ending for one person—filmmaker/actress Jennifer Westfeldt, who is Hamm’s long-time girlfriend. “I tell her everything and she definitely knows.” Assuring the secret is safe, he added, “She won’t tell anyone!”

The final episodes of Mad Men premiere on April 5.