"Bittersweet starting this next chapter without Carrie, but thanks to an extraordinary cast and crew, we are ready to go," he wrote. "Grateful for @rianjohnson and special thanks to George Lucas for creating this incredible world and beginning a story of which we are lucky to be a part. #IX."
"Last Jedi" director Rian Johnson appreciated the shout-out and responded himself, along with some other excited fans.
As Abrams mentioned, the cast will move forward without their beloved Carrie Fisher, who brilliantly played Leia for decades. But as revealed last week, old footage of her from "The Force Awakens" will be used in the film.
Fisher died in late 2016, after she had already filmed "Last Jedi," but before production began for "Episode IX."
Abrams said last week of using the old footage, "We desperately loved Carrie Fisher. Finding a truly satisfying conclusion to the Skywalker saga without her eluded us. We were never going to recast, or use a CG character. With the support and blessing from her daughter, Billie, we have found a way to honor Carrie’s legacy and role as Leia in Episode IX by using unseen footage we shot together in Episode VII."
In addition to Fisher's surprising return, Daisy Ridley, Adam Driver, John Boyega, Oscar Isaac, Lupita Nyong’o, Domhnall Gleeson, Kelly Marie Tran, Joonas Suotamo, and Billie Lourd will also return for the latest epic about a "galaxy far, far away."
Also back are Mark Hamill and Billy Dee Williams. After the ending of "Last Jedi," there were questions about Hamill's return as Luke, as well! Keri Russell will also join the cast.
"Episode IX" is out December 2019.