'Mad Men' Season 7 Spoilers: John Slattery on Joan and Roger's Relationship: 'Expect One Thing, Get Another'

(Photo: Reuters)"Mad Men" actress Christina Hendricks.

"Mad Men" returns to AMC on Sunday with a brand new episode "The Runaways" as part one of season seven winds down.

With just three episodes left in part one of the television series' seventh and final season, fans are already wondering about the upcoming series finale. However, "Mad Men" creator Matthew Weiner is notoriously tight-lipped about the plot of the television series, and very little is known about how characters such as Don Draper, Betty, Megan and Peggy will end up.

Fortunately, "Mad Men" star John Slattery recently discussed Weiner's talent for writing in relation to the series finale, offering hints along the way. The actor portrays head ad exec Roger Sterling on the series. While referring to his character's relationship with Joan Holloway (Christina Hendricks), Slattery said fans may not be happy with how the story ends for the pair.

"It isn't to say he's going to give the audience what they want, but it's much more interesting to expect one thing and get the other," he explained to HuffPost Live this week. "That's why Matt's as good as he is. Because he knows what the audience wants- you know, Joan and Roger, that's not what he's necessarily interested in."

Furthermore, Slattery claimed that he and the rest of the cast at "Mad Men" are just as oblivious as fans are when it comes to the intricate storyline on the show.

"I've stopped second-guessing," he said. "I think most of us on the show have stopped trying to figure out where it's going to go, because it never goes where you think it's going to go."

Weiner himself has offered few details on the series finale, only promising fans that more will learn more about "Mad Men" characters, including Jon Hamm's complex Don.

"I'm going to be leaving these characters in a place where they belong and I'm trying to take Don on a journey that will help you understand something about him," he told NPR.

"Mad Men" airs on AMC Sundays at 10 p.m. EST. The synopsis for this week's "The Runaways" is as follows: "Don gets a visitor from his past; Stan embarrasses a superior; Peggy helps Ginsberg with a problem; Harry discovers a new ally at the agency."