Mark Hamill, who will return to play Luke Skywalker in the upcoming Star Wars film has called the return to work without his co-star "bittersweet".

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

The new film will feature unseen footage of the late Carrie Fisher.

Episode IX will use footage that had been cut out of the The Force Awakens in order to wrap up Princess Leia's storyline.

Filming for the new movie began on Wednesday and will include Daisy Ridley, Adam Driver, John Boyega and Lupita Nyong'o.

Director JJ Abrahams released a statement saying: "We desperately loved Carrie Fisher. With the support and blessing from her daughter, Billie, we have found a way to honour Carrie's legacy and role as Leia in Episode IX by using unseen footage we shot together in Episode VII," he added.

Fisher died in late 2016 following a heart attack. A day later, her mother Debbie Reynolds, suffered a stroke and passed away.

The completed film will be released in the winter of 2019.