Ridley plays Rey in the sequel trilogy, and her arc will conclude with Episode 9: The Rise of Skywalker in December.
Filming wrapped on the production in February, two months before the title and first teaser trailer were unveiled at Star Wars Celebration.
Speaking to Jake Hamilton at the latter event, Ridley was asked how she found out how the whole thing ends.
“JJ [Abrams, director] told me and then I read the script, and it was sort of shifting,” she explained.
“The ending was always pretty similar and then I was told there was sort of a new slightly different beat added to what I was told.
“That was awesome, because it’s nice to be told the thing, and then you can experience it with the film-maker.
“But also – we don’t know how it’s going to turn out. We did the thing on this side of the camera.”
She also spoke about her final day on set, saying she was the very final actor to wrap.
“I was crying a lot. I was a mess,” she said, explaining that the likes of John Boyega, Oscar Isaac, Joonas Suotamo and Naomi Ackie had already completed work on their scenes.
“So it was emotional, like really emotional. So much ugly crying, like wailing. I couldn’t speak!”
Rey will likely take centre stage in the story, and it’s been revealed by Abrams that her origins will be explored further after Kylo Ren told her that she descends from “junk traders” in 2017’s The Last Jedi.
He told ABC: “I will say that we knew, going into this, that this movie, it had to be a satisfying conclusion.
“And we were well aware that that’s one of the things that’s been out there.
“I don’t want to say that what happens in Episode 8 [didn’t happen]. We have honoured that.
“But I will say that there’s more to the story than you’ve seen.”
Star Wars: The Rise of Skywalker is out on December 19 in the UK.