Jon Hamm: "Mad Men" Season 5 twists will surprise viewers

After nearly a year-and-a-half long hiatus, Donald Draper is finally coming back to the office.

The hit AMC series "Mad Men" returns for its fifth season at the end of this month, and many viewers are eagerly awaiting fresh installments of the Emmy-winning  1960s-set drama. The show's leading man, Jon Hamm, says they will be surprised.

A Golden Globe Award winner,  Hamm, recently spoke to CBSNews.com at the New York red carpet premiere of his new film, "Friends with Kids," and said  "Mad Men" fans should expect some unexpected plot twists for the new season.

"I think it will be a surprise and I think people will be pleasantly surprised and excited to see it," Hamm said of "Mad Men."

When we last saw Draper, the ad exec had become engaged to his secretary Megan (Jessica Pare), whom he sees as a suitable mother figure for his three children.

And while Hamm wouldn't divulge any specific plot details, the actor did acknowledge that it's been quite a while since we last saw Draper and the gang.

"It's been a long lay off. So we're excited to get it out there," he said.

The two-hour-long season premiere of "Mad Men" airs Sunday., March 25, at 9 p.m. (8 central) on AMC.