[RE-UPDATE: Halle Berry has confirmed that she will return for Days of Future Past. Scroll down for details.]

For a while now, X-Men: Days of Future Past has been sounding more and more like it would be one big reunion for the franchise. First, Patrick Stewart and Ian McKellen joined the returning First Class stars, followed swiftly by Hugh Jackman signing up for his seventh (!) appearance as Wolverine. Then, a few weeks later, Shawn Ashmore, Anna Paguin and Ellen Page came onboard.

Director Bryan Singer has already amassed an impressive lineup for his latest X-Men adventure, but a number of stars remain conspicuously absent from the cast. Rumors persist that Alan Cumming and Famke Janssen could feature into the time travel plot as Nightcrawler and Jean Grey. Now Singer himself has commented on two more potential returnees.

Speaking to E! Online, Singer commented on whether or not Halle Berry and Rebecca Romijn would make appearances in the film as Storm and Mystique, respectively. Here’s what he had to say:

“It depends on how it works out. I loved working with Halle, so all I can say is we’ll see what happens.”

Oscar winner Berry is among the bigger marquee stars to have starred in the X-Men franchise and hasn’t appeared since the tepidly received (to put it generously) X-Men: The Last Stand in 2006. Singer’s vague response with regard to her return could mean that negotiations are still ongoing. After all, the filmmaker has become known for his surprise announcements lately.

UPDATE: When speaking to S&A, Halle Berry confirmed that the deal for her return is being actively worked out. For more details go HERE.

RE-UPDATE: It’s official — Halle Berry is back as Storm in X-Men: Days of Future Past!

As for Romijn, fans will remember that the actress – like Jackman – briefly reprised her original trilogy role in First Class. Of course, that cameo didn’t require her to undergo the extensive makeup process to take on Mystique’s mutant form. Given the number of actors already slated to take part in Days of Future Past, Romijn’s character may not receive enough screen time to warrant such a grueling process. Cumming reportedly turned down an appearance in X-Men: The Last Stand for similar reasons.

Singer went on to promise that Days of Future Past will be the “biggest” film of the series and will aim to keep the long-running franchise fresh.

“I’m excited about all the actors. It’s an incredible cast. It’s a great story and it involves a lot of stuff that hasn’t been in ‘X-Men’ films before. New [kinds] of technology, science fiction aspects.”

Aside from James Marsden as Cyclops, the addition of Berry and Romijn would essentially complete the set of main players from the original X-Men trilogy (i.e., those actors who appeared in significant roles in all three films). At this point, anything is possible.

Do you want Berry and Romijn to sign up for more X-Men, or is Days of Future Past already becoming too crowded? Let us know in the comments.

The Wolverine hits theaters July 26th, 2013. X-Men: Days of Future Past hits theaters on July 18th, 2014.

Sources: EWE! Online