Carrie Fisher was supernaturally witty and magical: JJ Abrams

JJ Abrams says it would be impossible to imagine the end of "Star Wars" saga after almost 40 years without the story's heart, Princess Leia, played by the late Carrie Fisher, who had sort of predicted that he was not yet done with the galaxy far, far away.

Abrams, who successfully launched the franchise's sequel trilogy with 2015's "The Force Awakens", had not signed on for the upcoming "Star Wars: The Rise of Skywalker" but he stepped in after Colin Trevorrow left the project over creative differences with Lucasfilm.

Speaking at the D23 Expo where an exclusive trailer and poster from the much-awaited film was shown to the audience, Abrams opened up about working with Fisher, who died of a cardiac arrest on December 27, 2016 at the age of 60.

"The character of Leia is, in a way, the heart of this story. We couldn't possibly talk about the end of these nine films without Leia and we realised that we had footage from 'Episode 7' and we didn't even know that we could use it in a new way. So Carrie as Leia gets to be in the film," Abrams told fans here.

"People have asked me for many years now like 'what is she like', 'what's Carrie like'. It was always very hard to describe this. She was sort of supernaturally witty and magical in a way," he added.

The director, who worked with the veteran actor for the first time with The Force Awakens, then shared an anecdote about Fisher.

"I remember this thing that I had read and I actually thought I was mistaken... And I went back and I looked in her last book, 'The Princess Diarist', and in special thanks, she had written 'And special thanks to JJ Abrams for putting up with me twice'.

"Now, I had never worked with her before 'Force Awakens'. And I wasn't supposed to do this movie. So it was a classic Carrie thing to sort of write something like that... I couldn't be more excited to have you see her in her final performance as Leia, he said.

Fisher will appear as Princess Leia in "The Rise of Skywalker" after Abrams decided to incorporate the actor's unused footage from "The Force Awakens" in the film.

"The Rise of Skywalker" follows Rey (Daisy Ridley), Poe (Oscar Isaac), Finn (John Boyega) and the Resistance as they regroup after the events of 2017's "The Last Jedi" and fight the First Order and Kylo Ren (Adam Driver).

The ninth installment will bring the curtains down the Skywalker saga.

The film, which also feature the franchise veterans Mark Hamill and Billy Dee Williams, will hit the theatres worldwide on December 20 this year.