Days of Future Past acts as a sequel to both 2006's X-Men: The Last Stand and 2011's X-Men: First Class, as well as a follow-up to 2013's The Wolverine. Principal photography began in April 2013 in Montreal, Canada and ended in August 2013. The film was shot in 3D and is scheduled to be released on May 23, 2014.
The X-Men ensemble fights a war for the survival of the species across two time periods in X-Men: Days of Future Past. The characters from the original X-Men film trilogy join forces with their younger selves from X-Men: First Class in a battle that must change the past – to save their future.
The cast features characters from the original trilogy of X-Men films and the prequel X-Men: First Class.
Singer described the younger Xavier as being "a very different beast from First Class' feckless playboy. He's a wounded animal, bearded, long-haired, filled with rage at the way the world has treated him." According to Stewart, there will be an explanation for Professor X's return after he was vaporized by Jean Grey in X-Men: The Last Stand. Professor X's return was previously alluded to during a post-credits scene in X-Men: The Last Stand and a mid-credits scene in The Wolverine.
Singer stated that Mystique "is less innocent, evolved, getting closer to where Mystique was in X-Men 2." Lawrence revealed that Mystique is split off from Lensherr and Xavier and she has one mission of trying to assassinate somebody. She added "we’ve seen her [Mystique] in the future and what she becomes and this is kind of a turning point for her."
Singer described Storm as "one of the last surviving X-Men in this post-apocalyptic world". Berry stated that "there’s something very revealing and shocking about Storm in this movie. There are some things you find out about her that I think give you much more insight into who she is." When asked about if her pregnancy affected Storm's role, she replied "I wasn’t in as much as I was meant to be. My ever-growing belly was posing a constant challenge! What I could do was getting more limited so the role that I play is so different from what it could have been, due to my surprise pregnancy."
A military scientist and the head of Trask Industries who created a range of robots called Sentinels whose purpose is to hunt and destroy mutants. Dinklage stated that Trask "sees what he’s doing as a good thing — [his ambition is] definitely blind and he’s quite arrogant. He’s strove all his life for a certain respect and attention." He also stated that Trask is up against Richard Nixon.
When Ashmore was asked about what can be expected to see how his character's relationship with Rogue has evolved since X-Men: The Last Stand, he replied "they’re constantly having these relationship issues so we’ll see what happens."
Sy described Bishop as the guy from the future and that he fights for survival. Singer revealed that Bishop and along with Warpath, Sunspot and Blink are not fresh recruits. He stated "they’re more refugees that are living day to day in this hideously ruined world. They don’t have much hope in the future. They’re on the run and they join forces with the remaining X-Men to try to do this one last attempt at fixing the world."
Peters described Quicksilver as "very fast, he talks quick, he moves quick. Everything else is very slow compared to him, it’s like he’s always at the ATM waiting for the bastard in front of him to finish."
Producer Lauren Shuler Donner reported in August 2006 that renegotiations would be required to continue the X-Men main film series. Newer cast members of X-Men: The Last Stand were signed, while the older cast members were not. Donner stated, "There is forty years worth of stories. I’ve always wanted to do "Days of Future Past" and there are just really a lot of stories yet to be told." She later pitched Bryan Singer on doing a fourth installment of the previously established X-Men franchise, following the completion of X-Men: First Class. In March 2011, Shuler Donner revealed that the film was in "active development at Fox," saying, "We took the treatment to Fox and they love it... And X4 leads into X5".
20th Century Fox envisioned the 2011 prequel X-Men: First Class as the first film of a new X-Men trilogy. Donner compared the franchise plans to be similar to the darker, more mature content of the Harry Potter film series. Early reports had Matthew Vaughn and Singer returning to direct and produce the sequel, respectively. While still attached to the project as a director, Vaughn stated, "First Class is similar to Batman Begins, where you have the fun of introducing the characters and getting to know them, but that takes time. But with the second one, you can just get on with it and have a rollicking good time. That's the main difference between Batman Begins and The Dark Knight." Describing how the next movie could open, Vaughn stated, "I thought it would be fun to open with the Kennedy assassination, and we reveal that the magic bullet was controlled by Magneto." Singer has stated that the film could be set around the civil rights movement or the Vietnam War, and that Wolverine could once again be featured.
In November 2011, Simon Kinberg who co-wrote X-Men: The Last Stand and co-produced X-Men: First Class was hired to write the screenplay of the film. In May 2012, 20th Century Fox announced a July 18, 2014 release date for the film. The release date was later moved up two months earlier for a May 23, 2014 release. In August 2012, the title for the film was confirmed to be X-Men: Days of Future Past. The film is said to be inspired by Chris Claremont and John Byrne's X-Men comic book storyline, "Days of Future Past". The comic book storyline ran in Uncanny X-Men #141 and 142 in 1981 during Claremont and Byrne's run and introduced the idea of an alternate future for mutants that grew out of the Brotherhood of Evil Mutants killing an important senator, leading to a future where all mutants are hunted by Sentinels.
In October 2012, Matthew Vaughn left the director duties to focus on Mark Millar's The Secret Service 2014 film adaptation. He is still attached to the film as a producer.Bryan Singer was later announced as the director of the film. This is the third time that Singer is directing an X-Men movie.
"I decided that the next time I got myself involved in a movie that had a huge amount of attention already that I would use Twitter. As a way of connecting with fans, principally. And also as a way of clearing up misunderstandings so that people know. You know, they may hear that an actor is cast or hear somebody is going to be in it, but until I say it's so, that's the confirmation."
—Bryan Singer explaining the Twitter presence of the film.
X-Men: Days of Future Past is scheduled to be released in 2D and 3D theaters on May 21, 2014, in various international markets and on May 23, 2014 in the United States. It will be distributed by 20th Century Fox.
For the theatrical release of The Wolverine, a mid-credits scene teasing X-Men: Days of Future Past was attached. The scene, set two years after the events of The Wolverine, depicts Logan going through an airport security checkpoint while a commercial for Trask Industries plays in the background. All of a sudden, Logan notices that all the metal objects around him start to shake and levitate. He whirls around to find Magneto, who claims he needs Logan's help to combat a threat to all mutants. When Logan asks Magneto why he should trust him, all the people around them freeze as Professor Xavier approaches Logan and assures him that Magneto is telling the truth. Adam Pockross of Yahoo! Movies described the mid-credits scene as the coolest part of The Wolverine and stating, "Boom! And that's how you tease the next film: by giving us so much to chew on, yet so few answers."
In October 2013, the first official trailer for the film was released. Jason Callina of The Herald News gave the trailer a positive response stating "it is fantastic to see characters that I grew up with in the flesh.. we still have to wait till the end of May to see if Fox succeeded, but for now they have my interest." However, Ben Child of The Guardian criticized the trailer for the amount of characters that will appear in the film, stating "overloading the movie with superheroes might please fans of the comic books, but the rest of us will be chewing on our own spleens when the umpteenth brightly coloured dude turns up to spout one line of dialogue, then drop off the map."
In addition, two viral websites were launched before the release of the film: Trask-Industries.com in July 2013 and TheBentBullet.com in November 2013.
In July 2013, CKE Restaurant Holdings, Inc. and 20th Century Fox announced a promotional partnernship for the theatrical release of X-Men: Days of Future Past. The upcoming promotion includes advertising, in-restaurant merchandising, collectors’ cups and a new film-themed burger from CKE Restaurants such as Hardee's and Carl's Jr. Zachary Eller, senior vice president of marketing partnerships & promotions at 20th Century Fox stated "their fun and irreverent advertising campaigns are a great fit with our film and we couldn’t be more thrilled to join together to feed mutants everywhere!".
In December 2013, Singer announced the upcoming X-Men film, titled X-Men: Apocalypse. The film is scheduled to be released on May 27, 2016.Apocalypse will be a direct sequel to the film and will be directed by Singer.