Last month, it was confirmed that Hugh Jackman will return as The Wolverine in the X-Men: First Class sequel X-Men: Days of Future Past. The actor revealed that he will have more screen time in the follow-up, and teased that every actor who has appeared in a previous X-Men movie will be suiting up for the sequel.
"You wouldn't have enough room on the page after you've listed them all. Every other actor who's ever put on a superhero uniform will be in it. There's an element of time travel and, naturally, it will be action-packed."
The story is based on Chris Claremont and John Byrne's comic book arc in issues #141 and #142 of Ultimate X-Men from 1982. The time travel aspect Hugh Jackman mentioned stems from an alternate future where an important Senator is killed by the Brotherhood of Evil Mutants, which leads to all mutants being hunted down by Sentinels.