Due to the suspense, the presence of Cary Grant, the structure of the screenplay, and the frequent plot twists, many people believe this was a Sir Alfred Hitchcock film. Hitchcock was not involved in the making of the film at all. This confusion has prompted fans of the film to call it "the best Hitchcock film Hitchcock never made."
Audrey Hepburn was several years older than actresses who had already played Cary Grant's love interest back in the 1950s, such as Sophia Loren and Jayne Mansfield, which makes the fact that this movie often gets cited as an example of age gap relationships all the more peculiar. Hepburn was already in her mid-30s here, and "only" 25 years younger than Grant.
After finishing this film, Cary Grant was quoted as saying, "All I want for Christmas is to make another movie with Audrey Hepburn." Although it never happened, Grant was offered the role of Higgins in My Fair Lady (1964), and requested Hepburn as his co-star in Father Goose (1964).
In the scene where Audrey Hepburn is smoking a cigarette alone in her empty apartment, and Cary Grant enters, the backs of his ears had to be covered with masking tape, since the backlighting made them appear red.
In the scene in which Audrey Hepburn spilled ice cream on Cary Grant's suit, she used the term "assassination", and he used the term "assassin". This movie was in release shortly after the John F. Kennedy assassination in Dallas, and Universal Pictures was so worried about audience reaction to this dialogue, that they hurriedly re-dubbed the lines, using other terms, then sent out a revised reel to every theater in America showing this movie, telling them to substitute it for the old reel. Both old and revised reels may still be in circulation.
In the dining boat scene, the background music is a vocal version of the theme song "Charade". It contains only three stanzas, and the second stanza is completely different from the published lyrics. It reads: "And in a blaze of light/For you Romeo came/And it was closing night/The ending of the play."
Debut of the 1963 Universal logo, which featured a more realistic globe and outer space scene than the previous, as well as Van Allen belts. This logo would remain in use until Bird on a Wire (1990) (1990).
The music heard on the soundtrack during Charles Lampert's funeral, near the beginning of the film, includes an early version of Henry Mancini's theme for Two for the Road (1967) (1967), another Donen/Hepburn/Mancini collaboration.
Prior to making this movie, Cary Grant was originally offered Gary Cooper's role in the romantic comedy Love in the Afternoon (1957) (1957) (also co-starring Hepburn). Grant turned down that role because of the age difference between him and Hepburn. He was also committed to the role opposite Hepburn, eventually played by Humphrey Bogart, in Sabrina (1954) (1954).
Due to the studio's failure to secure the copyright, many shoddy versions of the film exist on DVD. Fortunately, a wonderful transfer also exists, on the flip side of the DVD of its own less successful remake, The Truth About Charlie (2002) (2002).
According to TCM, while filmed on location 1963 in France, and despite the distance from Hollywood the production was still effected by the political tensions escalating in America at the time. For example, the scene where Cary Grant passes an orange to a woman without using his hands was filmed on the same day President Kennedy blockaded Russian warships from bringing missiles to Cuba: Grant's intense focus on the scene and the great physical comedy helped the cast and crew remain calm during that crisis.
The trivia items below may give away important plot points.
Regina (Audrey Hepburn) asks Jean-Louis (Thomas Chelimsky) where he would hide a treasure, and he says he would hide it in the garden. Later, it is discovered that the money had been used to buy rare stamps at the Jardin des Champs-Ëlysées, the Garden.
The stamps depicted in the film are fictional counterparts of real rare stamps, but have their values raised by one. The stamps they represent are the Swedish orange three skilling, the "Hawaiian Missionaries" two cent blue, and the eighty-one para blue Romanian "cap de bour" on blue paper, in total worth about 3.6 million dollars in 2007.
The names Cary Grant's character uses are (in order): "Peter Joshua", a friendly stranger; "Alexander Dyle", Carson Dyle's brother; "Adam Canfield", a thief; and "Brian Cruikshank", a "T Man" (the character's real name and occupation). Only Brian is said to not be a divorcee.
Above the phone in Mrs. Lampert's room hangs a picture of the western side of Chateau du Chillon, a castle three kilometers from Montreux, Switzerland. The castle is not completely clear, but the distinctive flat-topped range of snow-capped peaks in the background is unmistakable. Ironically, the castle has been featured on several stamps.