Tom Cruise wanted to do another spy thriller, but he thought Salt (2010) and The Tourist (2010) were too similar to his Mission: Impossible (1996) franchise. He ultimately chose this project once it became an espionage thriller with comic elements.
The film's production partners, New Regency and Dune Entertainment, offset financing for the film by paying Tom Cruise a lower advance fee than he normally received. According to the Los Angeles Times, Cruise received eleven million dollars for Knight and Day (2010), not the twenty-plus million dollars he usually receives.
While leads Cruise and Diaz were promoting this movie they both appeared on the BBC's Top Gear Top Gear: Episode #15.5 (2010) where they competed in the traditional speed lap in the "reasonably-priced car." Their respective time records were 01m:44.2s and 01m:45.2s.