Bryan Singer is making sure that ‘X-Men: Days of Future Past’ won’t pull any stops when it comes to becoming one of the greatest comic-book movies of this generation. In an interview with Empire, he talks at length about the movie and getting advice from James Cameron, saying, “It's epic. I don't think people realize how big this movie's 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 wtih them. That's why 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."

Bryan Singer will be directing 'Days of Future Past'
He also compares the movie to the original ‘Days of Future Past’ comic, saying, “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."
He also adds that he’s planning to integrate every single film that has come out so far in the X-Men Universe, including ones that ‘took things in different directions’. He confirms that he will be announcing all official news through his Twitter, especially as more and more actors from the original films get confirmed for ‘Days of Future Past’.

James Cameron is an expert on multiverses and time travel
Right now, the returning cast members include Michael Fassbender, James McAvoy, Nicholas Hoult, Jennifer Lawrence, Patrick Stewart, Ian McKellen, Hugh Jackman, Shawn Ashmore, Anna Paquin, and Ellen Page.
Bryan Singer talks 'X-Men: Days of Future Past'