Last year's X-Men: Apocalypse introduced Sophie Turner as Jean Grey, but Famke Janssen portrayed the character in Bryan Singer's 2000 franchise launcher X-Men, and went on to appear in X2, X-Men: The Last Stand, The Wolverine, and X-Men: Days of Future Past.
Even after 20th Century Fox cast Turner as the younger Jean Grey, Janssen hoped that she would be given the opportunity to return as the older version. She felt that it was possible, since Sir Patrick Stewart and Sir Ian McKellen played Charles Xavier and Magneto even after James McAvoy and Michael Fassbender were introduced as their younger counterparts.
More recently, it appears that Janssen’s realized that her days in the X-Men franchise may be over. While speaking at a Denver Comic Con panel, the actress said:
It's the gift that keeps on, kept on giving. I think we're done, but it was really great while it lasted, and it lasted for a long time. It’s been nothing but a pleasure working not just as Jean Grey, which was such an honor because the comics were so fantastic already, but then the entire cast who I got to play with, all my fellow actors, thespians who are so talented. It was just a wonderful experience. I'm very grateful (via Comic Book).
However, that doesn't mean that Famke Janssen wouldn't play Jean Grey again if the opportunity presented itself. The actress claimed that she would "do anything" to reprise the role in a future X-Men movie, then added:
Jean Grey is a part of me. I would definitely come back to play her whenever they ask me.
Hugh Jackman and Patrick Stewart have already bid farewell to the franchise, and it does appear that Fox’s focus has shifted to younger actors. It seems highly unlikely that they would contact Janssen, or any original cast member.
