In her autobiography, Doris Day wrote that when she read this script, she remarked to her manager/husband Martin Melcher: "Thank God we don't have to do movies like that anymore!" His response: "We've already made the deal - there's no sense getting all steamed up about it!" Melcher had power of attorney for Day and signed her up for this film without her knowledge or consent.
In its review of this film, The New York Times remarked: "She appears to have reached that stage where massive wigs and nutty clothes and acrobatics cannot conceal the fact that she is no longer a boy."
Doris Day was needed for the closeups when Patricia is hanging underneath Irene Tsu's balcony. Day remarked that she got splinters in her hands because of this, and that night after shooting she couldn't even change the channel on her TV set.
Along with the concurrently filmed In Like Flint (1967), this was the last movie to be made in CinemaScope. (Most studios moved on to use Panavision for their widescreen formats.) Don Bluth unsuccessfully tried to resurrect the format with his film, Anastasia (1997).
Informed in 2011 by a film historian that this film had found new favor among film school students admiring the picture's eclectic mix of satire, slapstick and action, Doris Day admitted she hadn't watched the movie in decades and may have to give it a second look.
The ironclad contract that agent-husband Martin Melcher had signed his wife Doris Day up for was fairly typical of what he engineered behind her back. Upon his death from either a ruptured appendix or an enlarged heart the following year at age 52, it was discovered that Melcher had lost millions of Day's money in unwise investments, leaving her essentially penniless.
Although many critics have commented on the lack of chemistry between Doris Day and her co-star Richard Harris, the two were said to have got on very well and enjoyed working together. Harris claimed that he "learned more about comedy from Doris Day than four years at the Royal Academy". However, this is probably not true as he attended the London Academy of Music and Dramatic Art (LAMDA), not the Royal Academy of Dramatic Art (RADA).
Richard Harris was a hot commodity at the time, coming off the success of his Oscar-nominated role in Lindsay Anderson's _This Sporting Life_. He was so disappointed with the final version of Caprice (1967) that he publicly disowned it. Harris scored greater success very shortly after, however, with the release of Joshua Logan's Camelot (1967).
When Doris goes in to the movie theatre, in another attempt at getting a snip of Si Long's hair, she's in the balcony behind one amorous couple, as well as beside an amorous couple. The couple aside of Doris features an uncredited Barabara Feldon, who portrayed agent 99, on Get Smart, which was another 'spy series' reference.