Mark Hamill has weighed in via Twitter on the news that Carrie Fisher will appear in the upcoming Star Wars, sending out a tweet calling it “bittersweet.” He also confirmed that he and Billy Dee Williams will be in the upcoming installment.

“It’s bittersweet facing my final chapter without her-She is simply irreplaceable,” said Hamill. “I’m finding solace in the fact that she won’t BE replaced & would love the worldwide outpouring of affection from those who loved her when they heard the news.#CarrieOnForever

Hamill earlier tweeted the news that he would again appear in the film, and dropped another choice tidbit by confirmingBilly Dee Williams will be back.

It's finally fine to admit #ImInIX-Billy Dee @realbdw too-which is long overdue (No one's ever really gone) Now only 17 months of "no comment"s when asked about it to avoid revealing details or fueling speculation #SeeYouAroundKids https://t.co/REUTX571c6 — Mark Hamill (@HamillHimself) July 28, 2018

Hamill’s tweets come after Todd Fisher, the brother of the late Carrie Fisher, said he “couldn’t be more personally thrilled and happy that our Carrie will reprise her role as Princess Leia in the new and final Star Wars Episode IX using previously unreleased footage of her shot for Star Wars: The Force Awakens.”

Todd Fisher issued his statement in the wake of announcements that Carrie Fisher would appear in the upcoming film using previously filmed footage.

“As we, her family, as well as her extended family of fans around the world so believe, Carrie’s ‘Princess Leia is forever entrenched in the franchise and her indelible presence is fundamental to the film,” Todd Fisher said. “J.J. Abrams understood Carrie’s iconic role, and he has masterfully re-crafted this final entry to include this unused and very last footage of Carrie ever taken, without resorting to CGI or animatronics. Our family and her fans will look forward with great anticipation for this one! Her force will forever be with us!”

Todd Fisher was also the author of My Girls: A Lifetime with Carrie & Debbie, in which he talked about his sister and mother, Debbie Reynolds.

Star Wars: Episode IX will begin filming August 1 at London’s Pinewood Studios, with Naomi Ackie and Richard E. Grant joining the main cast that also will include Mark Hamill, Anthony Daniels, and Billy Dee Williams as Lando Calrissian as had been tipped. Ackie and Grant Shutterstock Disney and Lucasfilm also said that the role of Leia Organa will be played by Carrie Fisher, using previously unreleased footage shot for Star Wars: The Force Awakens. Fisher, who starred in the original trilogy with Mark Hamill and Harrison Ford and appeared in 2017’s Star Wars: The Last Jedi, died in December 2016. “We desperately loved Carrie Fisher,” director J.J. Abrams said in announcing the news on StarWars.com. “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 [Lourd], 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.” Abrams directs the script he co-wrote with Chris Terrio. The plot to the purported finale of the Skywalker Series of Star Wars pics is under wraps, so no clues as to the newcomer roles for Ackie and Grant. The main cast from The Last Jedi also is back, Lucasfilm and Disney confirmed: Daisy Ridley, Adam Driver, John Boyega, Oscar Isaac, Lupita Nyong’o, Domhnall Gleeson, Kelly Marie Tran, Joonas Suotamo and Lourd. John Williams, who has scored every chapter in the Star Wars saga, also will return. The film has a December 20, 2019, release date.