Knight and Day is a 2010 American satirical action comedy film directed by James Mangold and starring Tom Cruise and Cameron Diaz. The film was the second on-screen collaboration of Cruise and Diaz after Vanilla Sky (2001). The film follows June Havens (Diaz), a classic car restorer, who unwittingly gets caught up with Roy Miller (Cruise), an eccentric secret agent, as Roy is on the run from the CIA.

The film's investors offset funding costs by paying Cruise a lower advance fee and providing him a share of revenue only after the financiers were repaid their investment in the production. Filming took place in several locations, mainly in several cities located in Massachusetts, while other scenes were filmed in Spain and parts of Austria and Jamaica.

Knight and Day was released in the United States on June 23, 2010, and received mixed reviews from critics with praise for its action sequences and the performances of Cruise and Diaz, but criticised its script. The film grossed $262 million worldwide and was remade in Hindi as Bang Bang!, with Hrithik Roshan and Katrina Kaif in the lead roles.