The 37-year-old Canadian-American actor opened up about the 39-year-old German actress to reporters at the Hollywood Foreign Press Association and InStyle 2016 Golden Globe Awards season celebration Tuesday in West Hollywood.
"One of the most attractive things to me about Diane is how confident she is in herself as a woman and in her beauty and how much self-respect she has and the way that manifests itself in the way she dresses," Jackson told The Hollywood Reporter.
"For Diane, having gone through the modeling side of the business in her youth, her fashion sense is a true expression of her own desire and her own style," he explained. "I find that tremendously sexy. She knows that she's well-dressed, but she doesn't have to obsess about it."
Kruger was previously married to French actor Guillaume Canet and has been with Jackson since 2006. The Fringe actor also discussed Kruger with People, telling the magazine he and the actress continuously "work at" their relationship.
"It's not always easy because nothing in life that's worth doing is always easy," he said. "I understand at 37 better than I ever did at any other time in my life what the phrase 'love's labor' really means. It's work. But it's work that rewards itself many times over."
Jackson is best known for playing Pacey Witter on The WB drama Dawson's Creek, and currently portrays Cole Lockhart on Showtime series The Affair. Kruger is slated for Fathers and Daughters with Russell Crowe and Infiltrator with Bryan Cranston.