The 29-year-old British actress and Righton tied the knot in 2013 after two years of dating. When asked to dish on her husband, the Anna Karenina actress said the idea of marrying him simply seemed "fun."
"When James proposed, I just thought, 'Well, never done that before,'" Knightley told Glamour. "It seemed like a fun thing to do."
The actress also discussed her upcoming project during the interview, telling the magazine that her Begin Again co-star Adam Levine played "a dickhead very well."
"Actually, I admire him being so willing," she continued. "To play a dickhead is quite a big thing when you are trying to break into film and you want to be likable."
As for why she decided to break her dramatic-films run and do a romantic comedy, Knightley explained she thought of the experience like a "little holiday."
"With a feel-good film you are always risking going way too cheesy. ... But maybe I can have a little holiday where I'm not playing a character who is being destroyed."
Knightley's full interview for the fashion glossy will be unveiled on June 17, when the July issue of Glamour hits stands.