According to The Verge as reported on Jan. 26, 2013, film director Bryan Singer has confirmed the three actors: Anna Paquin, Ellen Page, and Shawn Rashmore, are returning to the Marvel Universe in "X Men: Days of Future Past".
Singer, also a Tweeted about how he's watching the SAG Awards while working on the "X-Men" script using an old-fashioned writing utensil. He is watching Jackman smiling as Singer remarks that he should stop getting hair cuts.
A Twitter post by Bryan Singer reveals the details about the actors:
It appears that Singer is basing his casting couch off the classic comic X-men comic book where the Senator in power is assassinated which causes an alternate timeline that Kitty Pryde must prevent. The dreaded new timeline is a world where just about the entire population of mutants on Earth are exterminated by Sentinels and it is Kitty's duty to back in time to prevent that from happening.
The story unfolds simultaneously in both the times and also is tying this movie into both the original prequel, "X-Men First Class, with the previous three movies, two which Singer had already directed.
Of course, Hugh Jackman that will be playing himself will have no youthful actor taking his spot, because his healing factor gives him long life.
Also, Jennifer Lawrence will be returning as Mystique, a member of the Brotherhood of Mutants and loyal follower to Magneto. Question might arise will the future jilted lover of Magneto will be encountering her youthful self.
There are still unanswered questions in regards to "X-Men: Days of Future Past" such as Daniel Cudmore's return as Colussus, and who will play Rachael Summers, the future daughter of Scott Summers and Jean Grey. Also, with actress, Famke Janssen, it is unknown wether or not she'll return to "The Phoenix" either.