We know that the late Carrie Fisher will posthumously appear, for the final time, as Leia Organa in next year's J.J. Abrams-directed Star Wars: Episode IX.
Her role is said to consist of mostly unused footage from Star Wars: The Force Awakens and Star Wars: The Last Jedi and according to Fisher’s brother, Todd Fisher, Lucasfilm has a lot of leftover material to work with:
“There’s a lot of minutes of footage,” Fisher told Good Morning America. “I don’t mean just outtakes. This is unused, new content that could be woven into the storyline. That’s what’s going to give everybody such a great kick. It’s going to look like it was meant to be. Like it was shot yesterday. We’re not allowed to talk about the details of anything. But we’re thrilled at what’s been done.”
Star Wars: Episode IX is set for release on December 20th 2019.