When X-Men: Dark Phoenix started shooting last month in Montreal, many fans had hoped that the studio would issue a full cast list, and/or confirm a rumor that Jessica Chastain was being sought for the movie, but it turns out she has in fact signed on. The news broke from the actress herself, sharing a photo on social media with James McAvoy, while asking both her new co-star and writer-director Simon Kinberg if they're "ready" for her in Montreal. Here's what the actress had to say below.

"Hey @jamesmcavoyrealdeal you ready for me up in Montreal? Im gonna make you cry so hard #xmen @simondavidkinberg"
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Reports first surfaced about Jessica Chastain being cast in Dark Phoenix in June, when it was rumored that she was being eyed to play the primary villain, Shi'ar Empress Lilandra. The actress wouldn't clarify the character she's playing on her Instagram post, but her cryptic statement about making James McAvoy cry certainly could be an indication that she is playing a villain. If she is in fact playing Shi'ar Empress Lilandra, it will mark the first time this character has been seen on the big screen, but she does have a big presence in the Dark Phoenix comics this story is based on.

Shi'ar Empress Lilandra, a.k.a. Lilandra Neramani, was created by Chris Claremont and Dave Cockrum, making her first appearance in Uncanny X-Men #97 in February 1976. Lilandra is the sister of D'Ken and Deathbird, an heir to the Shi'ar empire, in the midst of some intense family strife. After turning against her brother D'Ken, who ruled the empire, Lilandra fled to Earth, where she discovers that she has a powerful bond with Charles Xavier (James McAvoy), which may very well be explored in this upcoming movie. As far as the Dark Phoenix saga goes, the X-Men and the Dark Phoenix help stop D'Ken's nefarious plan, but Lilandra wants to imprison the Dark Phoenix, the being that lives inside Jean Grey, so it's possible that story may be explored.

This news comes just days after the production has found their young Jean Grey, with actress Summer Fontana signing on. Very little is known about how large a role she plays, but you may recall there was a young Jean Grey flashback in X-Men: The Last Stand back in 2006, although that story was essentially eliminated through the events of X-Men: Days of Future Past, leading to this new Dark Phoenix reboot. The new story will be set in the 1990s, following the prequel trilogy's format of each movie being set a decade apart.

This movie will serve as Simon Kinberg's directorial debut, after serving as a writer and producer on X-Men: Days of Future Past and X-Men: Apocalypse. The cast of the X-Men prequel trilogy will return, with Sophie Turner (Jean Grey), Jennifer Lawrence (Mystique), Nicholas Hoult (Beast), Tye Sheridan (Cyclops), Kodi Smit-McPhee (Nightcrawler), Evan Peters (Quicksilver) and Alexandra Shipp (Storm) all returning. 20th Century Fox has set a November 2, 2018 release date for X-Men: Dark Phoenix, which will be the third X-Men movie released next year, following The New Mutants (April 13, 2018) and Deadpool 2 (June 1, 2018). While we wait for more details, take a look at Jessica Chastain's Instagram post below.