Peter Capaldi plays a doctor with the World Health Organization and is credited as "W.H.O. Doctor." Two months after the film's release, the BBC announced he would be portraying the title role in Doctor Who (2005).
Matthew Fox had a bigger role in the film. He was a supporting character who in the end would be set up as a (human) villain for the sequel. Due to the constant re-writes and editing, his role in the final cut was reduced down to only 5 lines of dialogue.
A total of 85 prop machine guns, rifles and pistols to be used for scenes filmed in Hungary, were confiscated by counter-terrorism customs officers in Budapest, Hungary after being flown in from London. Hungarian authorities said the guns could be activated by removing the screws filling the end of the barrels. Hungarian law requires weapons to be deactivated only if the process is irreversible. The movie's weapons supervisor, Bela Gajdos, commented that a permit for the weapons had been issued by Hungarian police. Reports claimed that main actor Brad Pitt was "furious" at the seizure but producers said it had not delayed filming.
Paramount executive Marc Evans and Adam Goodman, the president of production did not like the original cut (which has the Russian ending) as both men felt that it was incoherent and abrupt. They brought in Damon Lindelof to view the cut and he suggested to them either to add new scenes to improve the coherence or do a complete third-act rewrite and risk additional resource plus re-shoots. Lindelof recalled: "So when I gave them those two roads and they sounded more interested in Road B I was like, 'To be honest with you, good luck selling that to Paramount."
Filming took place in several areas of the UK including Cornwall, England where the UN control room scene was filmed alongside scenes on the Ministry of Defence Primary Casualty Receiving Facility (PCRF), RFA Argus (AS on the flight-deck). Filming also took place in Glasgow, Scotland with the streets made to look like those in Philadelphia with many American cars, trucks, taxis and street signage shipped in from the USA. Also filming took place in Valletta, Malta.
The original cinematographer was Robert Richardson. He left the film near the end of principal photography to begin working on Django Unchained (2012), so shooting was completed by Newton Thomas Sigel. Reshoots were shot by Ben Seresin. Richardson, who received sole credit in early promotional material, later had his name removed from the film, reportedly because it was converted to 3-D against his wishes, and Seresin was given sole credit instead.
In the beginning of the trailer released in March 2013 while Brad Pitt's family is having breakfast the radio in the background mentions a flight which landed without permission before martial law is declared in Russia. This is likely the infamous (in zombie lore) Flight 575 which, after landing, disgorged its passengers which had all been turned.
In a high-six-figure deal, Paramount Pictures acquired screen rights to the Max Brooks novel "World War Z: An Oral History of the Zombie War." Brooks' follow-up to satire "The Zombie Survival Guide" sparked a bidding battle, with Warner Bros. and Leonardo DiCaprio's Appian Way on the other side of the table from Paramount and Brad Pitt's Plan B.
The trivia items below may give away important plot points.
Originally, the film had a different ending: the plane lands in Moscow rather than crashing in Wales. The passengers are rounded up, and the elderly and sick are executed. Gerry is drafted into the Russian army. An unknown period of time passes, and we see Gerry fighting the zombies. He realizes the zombies are weak in the cold. The film ended with him getting back to the USA and leading a D-Day like invasion against the undead on the Oregon coast. The ending that was used instead made the movie less brutal and ended it with a glimpse of hope.
The rewrite was almost at 60 pages long and cost an additional $20 million more. In addition to the new opening and the rewritten third act, the following snippets were added by Drew Goddard and Damon Lindelof, with Christopher McQuarrie doing uncredited dialog sharpening:
At the family breakfast, the TV news report of the zombie sighting.
Rachel's asthma attack
Gerry's phone call to Karen from South Korea to Jerusalem