Anna Paquin, who played Rogue in the first three films, as well as Ellen Page (Kitty Pryde) and Shawn Ashmore (Iceman) will be appearing in Fox's follow-up to 2011’s mutant prequel, X-Men: First Class.

PHOTOS: 'X-Men: First Class’ Style Gallery

Singer directed Fox’s first two X-Men films, but left 2006’s X-Men: The Last Stand in the hands of Brett Ratner when he departed to helm Superman Returns for Warner Bros. Ratner's X-Men film upset some fans because it killed off a number of key characters.

Singer jokingly thanked Ratner for allowing the mutants played by Paquin, Page and Ashmore live so he could use them in the new film.

Days of Future Past, based on a 1981 story in Marvel Comics' Uncanny X-Men, will involve both the 1960s First Class mutants, and a future version of the original trilogy characters, who live in a world in which mutants are hunted down.

First Class stars James McAvoy, Michael Fassbender, Jennifer Lawrence and Nicholas Hoult are on board for the film, which is eyeing an April start date and is slated for a July 18, 2014 release.

As The Hollywood Reporter wrote in December, sources indicate stars of the original trilogy will appear mostly in scenes depicting a dystopian future, so time commitments for the actors are likely to be minimal.

Fans of the Marvel franchise won't have to wait until 2014 to get a mutant fix. Hugh Jackman returns in The Wolverine July 26.

Email: aaron.couch@thr.com

Twitter: @AaronCouch