Val Kilmer met Robert Downey, Jr. for the first time at a Hollywood party. A week later, he received the screenplay for this film, and agreed to do it before he'd even finished reading it. Upon agreeing, and much to his delight, he was informed that Downey had already been cast.
Val Kilmer walked around in a five hundred dollar pair of Louis Vuitton driving shoes, and wore nail varnish, while experimenting with several variations of speech patterns for the role. Kilmer also noted this was done much to his son Jack's chagrin.
Shane Black had been suffering from writer's block. It ultimately took him over a year and a half to write the script for this film. He then had enormous trouble trying to sell it. His former cachet, as being the highest paid screenwriter, meant nothing when he was shopping his screenplay around. Eventually, he took it to Producer Joel Silver, who gave him his first break back in 1987 when he bought Lethal Weapon.
Joel Silver noted that the film was originally budgeted at ten million dollars, because Warner Brothers was not confident in the premise. The film ran over, and the final budget was fifteen million dollars. Warner Brothers loved the film when it was screened, and immediately opened it at the 2005 Cannes International Film Festival in a high-profile capacity.
Warner Brothers was willing to produce the movie with a larger budget, if Harrison Ford was to play the detective. When he passed on it, several other options were briefly considered before Val Kilmer was offered the role.
Shane Black read several stories by Raymond Chandler when writing this script. As a result, the story is divided into chapters and the chapter titles come from Chandler works. Specifically: 1. "Trouble is My Business", 2. "The Lady in the Lake", 3. "The Little Sister", 4. "The Simple Art of Murder", and Epilogue: "Farewell, My Lovely".
The movie shares its title with a song from the soundtrack of the James Bond movie Thunderball (1965). "Mr. Kiss Kiss Bang Bang" was recorded first by Shirley Bassey, and then Dionne Warwick after Composer John Barry had chosen the title when he read a magazine article which mentioned that was how Bond was known in Italy. However, the producers got cold feet at the last moment, and asked him to write a title song, "Thunderball", which was performed by Tom Jones. KKBB was relegated to an instrumental-only status within the movie. Both versions of "Mr. Kiss Kiss Bang Bang" were released many years later, and "Kiss Kiss Bang Bang" has since become a slang description of the James Bond-style spy genre.
The film's original title was "You'll Never Die in This Town Again". When Harmony is seen on the bus leaving Indiana at age sixteen, she's asleep with the Johnny Gossamer book, "You'll Never Die in This Town Again" in her lap.
Because of its modest budget, Warner Brothers granted Joel Silver the distinction of overseeing the film personally, allowing Shane Black to only have to answer to him, instead of numerous studio heads.
The opening part, taking place at Harlan Dexter's mansion, was shot at Shane Black's mansion. In the years between Black's last produced feature, The Long Kiss Goodnight (1996), and this one, Black had become infamous for throwing similar large, extravagant parties at that mansion, filled with the same kind of industry big-wigs and up-and-comers.
In reference to the "Ike, Mike, and Mustard" quote, Ike and Mike are diner slang for salt and pepper shakers. Also, pre-1950s, an "Ike, Mike, and Mustard" joke was an off color joke, generally with sexual references, that wouldn't be told in polite or mixed company.
WRITER TRADEMARK: (Shane Black): (disarmed gunman): While being held at gunpoint, Gay Perry demonstrates how easy it is to disarm a non-professional gunman, as most of them fail to keep a minimum distance of five feet from their targets. Shane Black often writes scenes where the hero is able to disarm a gunman who makes this mistake, most notably in The Last Boy Scout (1991) and The Long Kiss Goodnight (1996).
In one scene, Harry Lockhart is prompted to read lines from a script sample. The first line he reads ends with the phrase "go spit", which is also a catchphrase of Roger Murtaugh (Danny Glover) in the Lethal Weapon movies.
The phrase "kiss kiss, bang bang" appeared in the 1960s as an overseas slang for spy movies, especially James Bond movies. It was popular in Europe and Japan. It first appeared as a film title for Kiss Kiss - Bang Bang (1966), a 1966 spy comedy made in Spain with Italian financing. It was also the title of famed critic Pauline Kael's second published collection of reviews. Kael wrote that she chose the words as her title because they are "perhaps the briefest statement imaginable of the basic appeal of movies."
At one point in the film, Gay Perry reveals that Colin Farrell is up for the role, for which Harry is auditioning. Val Kilmer had previously played Philip, father of Alexander the Great (Farrell) in Alexander (2004).
Robert Downey, Jr. and Val Kilmer have played famous superhero characters in movies. Downey played Tony Stark, a.k.a. Iron Man, in the Marvel Cinematic Universe, while Kilmer played Bruce Wayne, a.k.a. Batman, in Batman Forever (1995).
Val Kilmer, Robert Downey, Jr., Michelle Monaghan, and Shane Black were all involved with DC or Marvel property. Kilmer played Batman in Batman Forever (1995), Downey as Iron Man in the Marvel Cinematic Universe, Monaghan as Wonder Woman in Justice League: War (2014), and Black directed Downey in Iron Man 3 (2013).
The trivia items below may give away important plot points.
Towards the end, Harry attributes Perry's dubious survival to when "the studio gets paranoid about a downer ending." The same rationale caused a change to the endings of Shane Black's prior screenplays for Lethal Weapon 2 (1989) and The Long Kiss Goodnight (1996).
Body count: thirteen: Protocop actor (falls off Harmony's balcony); Richie (shot by woman on fire escape); Veronica Dexter (the "lady in the lake"); Jenna Lane (suicide); Mr Frying Pan (shot by food stand owner); Pink Hair Girl (shot by Mr Fire); Mr Fire (shot by Harry); Dexter's Clinic guard (shot by Harry); Aurelio (shot by Perry); Dexter's goon on bridge (shot by Perry); Harlan Dexter (shot by Harry); two goons on freeway (shot by Harry).
There is a clue to the murder plot in a shot of a defective hotel "No Vacancy" sign. The sign flashes "No Vac". In the Hitchcock film Vertigo (1958), Kim Novak plays a woman who doubles for a murder victim.