Dear Brigitte was based on the 1963 novel Erasmus With Freckles, written by Westwood, CA, dentist-turned-author John Haase. According to items in the 19 Jun 1963 and 1 Jul 1963 DV, the story piqued the interest of singer-actor Bing Crosby, who wished to acquire the property as a star vehicle to be developed at Paramount Pictures or Walt Disney Pictures.
       Later that year, however, the 26 Oct 1964 LAT indicated that the project had moved to Twentieth Century-Fox Film Corp., with James Stewart assuming the leading role. The casting marked a reunion between Stewart, director-producer Henry Koster, and writer Nunnally Johnson, following their collaborations on Mr. Hobbs Takes a Vacation (1962, see entry) and Take Her, She’s Mine (1963, see entry). A 14 May 1964 LAT article noted that child actor Bill Mumy was discovered in a Sunday school class taught by Stewart’s wife, Gloria. The 8 Apr 1964 DV suggested Shelley Fabares was considering a role in the picture, but she does not appear in the final film.
       On 15 May 1964, DV reported that Stewart had left for ten days of location filming in Paris, France, where actress Brigitte Bardot agreed to shoot a cameo appearance. According to a 29 May 1964 DV production chart, principal photography began 18 May 1964, and the 1 Jun 1964 LAT stated that Bardot finished her scenes in just three days. As this was the French star’s first role in an English-language film, a 4 Jun 1964 LAT article claimed that Peggy Moran, wife of producer Henry Koster, served as her dialogue coach. The 25 May 1964 DV reported the unit’s impending return to Los Angeles, where the remainder of the picture would be completed. However, the 21 Jul 1964 LAT indicated that additional location work was done in Sausalito, CA.
       According to a 20 Jul 1965 DV news story, scenes shot at the University of California, Los Angeles (UCLA) were not identified as such in the film. Additionally, writers Nunnally Johnson and Hal Kanter revised much of Haase’s “liberal” dialogue to make the picture less political. Kanter, who received sole credit for the screenplay, told the 15 Sep 1964 LAT that Koster was responsible for the addition of Ed Wynn’s character, who acts as a “one-man Greek chorus” narrating the action.
       Dear Brigitte opened in New York City on 27 Jan 1965, and the 16 Feb 1965 LAT announced that the Los Angeles engagement was scheduled to begin the following day.