Phoebe Waller-Bridge worked in the production for about six months, writing and producing (she was also set to star as Jane) before exiting the project due to creative differences.
When Jane and John first meet their first words to each other are "Hi" and "Hi" respectively. They call their supervisor "Hihi" after each initial interview where the computer greets them with "Hihi" instead of a standard greeting.
A pilot for a "Mr. and Mrs. Smith" TV series was filmed in 2007 starring Martin Henderson and Jordana Brewster. However, the series failed to materialize, and the pilot is available to watch on YouTube.
The series was described by Simon Kinberg as a "Married with Children" with guns.