The lovebirds will be celebrating 14 years of marriage next month, and while speaking with ET at a fan screening for Younger in New York City on Monday, the 50-year-old actor teased that he's planning something special for his wife.
"That's where I keep secrets," Hermann, who portrays Charles Brooks on the comedy-drama series, told ET's Keltie Knight. "Yeah, good things planned."
Hermann and Hargitay, 54, first met on the set of Law & Order: SVU, and tied the knot in Santa Barbara, California, on August 28, 2004. The two share three kids together -- sons August, 12, and Andrew, 6, and daughter Amaya, 7.
Later in the interview, Hermann also opened up about his co-star, Hilary Duff, who is expecting her second child, a baby girl, and her first with boyfriend Matthew Koma. He admitted everyone on set kept their lips sealed so that the 30-year-old actress could reveal the exciting news herself.
"The thing about the show is about secrets and so, we keep a good secret," he explained. "[We may] have the grandest baby shower planned ever and you just don't know about it yet. I don't know about it yet because she kept a secret."