The film follows Jackman's superhero Wolverine as his consciousness travels back to his 1970s-era body and tries to persuade benevolent professor Charles Xavier, played by James McAvoy, and Xavier's rival Magneto, played by Michael Fassbender, to team up and stop a war profiteer from using machines he developed to destroy all mutants.
McAvoy and Fassbender previously played the roles in the 2011, 1960s-set prequel, X-Men: First Class, while Jackman, Patrick Stewart and Ian McKellen played Wolverine, Charles and Magneto in 2000's X-Men, 2003's X-2: X-Men United and 2006's X-Men: The Last Stand.
Days of Future Past features McAvoy, Fassbender, McKellen and Stewart as the characters in their respective time periods, with Wolverine acting as a bridge between the eras. Jennifer Lawrence and Nicholas Hoult also reprise their First Class roles as Mystique and Beast.
"It is sort of filmed, in a way, like two films because the beginning was the future, which was like an incredible reunion for all of us and then on came the younger, more inexperienced actors," Jackman joked with reporters at a recent cast press conference in New York.
"And the whole time -- as intense as the material was -- it was unbelievable. And I am probably uniquely qualified to say -- having worked with everyone -- that being on the set throughout the whole thing was a joy."
"This film's [cast] has always had a great bond from the beginning and I see and felt it with you guys when you are working together. You have a great bond," Jackman said to McAvoy and Fassbender, who sat alongside him on the panel. "Everyone is very passionate about it, takes it very seriously, but has a lot of fun. In terms of intensity, I remember very clearly, sitting at the back of that private plane, watching these two guys go at it [in a fight scene,] and I say this absolutely sincerely, that I was never sure it could be possible to fill the shoes of Ian and Patrick and what they did in X-Men. When I saw First Class, I realized these guys did it with such aplomb and confidence. Not only did they feel like younger versions of those characters ... they also have made it their own. It is an incredible feat, what you guys did. I think the way [Stewart and McKellen] anchor the films in X1, these guys anchor the film in this."