"It's epic. I don't think people realize how big this movie is going to be. We get to bring both casts together. We've cracked it in a way that it makes sense. I had a two-hour conversation with James Cameron about time travel, string theory, multiverses and all that. You have to create your rules and stick with them. That's why The Terminator and Back to The Future work so well. And there are certain mechanisms in X-Men, certain powers, perceptions and characters, that make this possible."
The director also revealed he is taking into account every one of the past X-Men movies (X-Men, X2: X-Men United, X-Men: The Last Stand, and X-Men: First Class) in crafting the story for X-Men: Days of Future Past.
"I'm taking into account every movie - I'm not just grabbing my first two movies and First Class and smashing them together. I'm taking into account the entire universe as it's been laid out so far on the screen, and really respecting it and trying to work with that. People took things in various directions, so there's some clean-up. But ultimately I'm not just ignoring them either."
He also spoke about how closely this superhero sequel follows the comic books.
"It has a lot of aspects of the comic. The actual comic of Days Of Future Past had a whole ton of stuff going on, so it's like any of these things; you have to distill it. But I think the fans will be pleased that some of the most exciting parts of Days Of Future Past are going to be connected to this movie."
Over the weekend, the filmmaker revealed on his Twitter page that Ellen Page is returning as Kitty Pride, Anna Paquin is back as Rogue, and Shawn Ashmore is reprising his role as Iceman. The director stated that he plans to use his Twitter page to reveal more news about the upcoming adventure.
"I'll be using Twitter as an avenue. I think Twitter is an amazing thing. Very often something gets out there in the rumor-sphere, and people start building up an impression of something that might not be right. So what I want to do is just little by little drop out whatever information is official."
When asked if he plans on using another "F-bomb" like in X-Men: First Class, the director revealed they have another use of the F-word in store for this sequel.
"We're going to have another one in this one. We have another one coming up!"
X-Men: Days of Future Past is based on the Days of Future Past comic book arc by Chris Claremont and John Byrne, which follows the mutants as they are hunted down by Sentinels in an alternate future.
X-Men: Days of Future Past was released May 23rd, 2014 and stars Hugh Jackman, James McAvoy, Michael Fassbender, Jennifer Lawrence, Halle Berry, Nicholas Hoult, Anna Paquin, Ellen Page. The film is directed by Bryan Singer.