Ridley, 27, recently spoke with British GQ about her time on set, calling Fisher's absence "difficult."
Ridley not only lost a friend and co-star after Fisher suffered a heart attack in 2016, but in order to complete the most recent "Star Wars" trilogy, Ridley had to film scenes that would be spliced together with unused footage from "The Force Awakens."
“It was definitely difficult,” the actress said in the interview, published Tuesday. “It was emotional doing it because you’re also weirdly picturing her. You’re not picturing how the scene is going to be.”
Ridley also said she never brought up Fisher's death with co-star Mark Hamill, who had known the actress for 40 years before she passed away.
However, Ridley did mention that she reached out to Billie Lourd, Fisher's daughter and fellow "Star Wars" alum, to "ask Billie how she was doing."
And while the scenes without Fisher were hard to film, Ridley said they'll be tough for viewers to watch, as well.
“It’s really sad. And it’s going to be really sad,” Ridley said. “But also, it’s amazing that they have all this footage that is woven into the story in such a strange way.”
Ridley also let a hint slip about the movie's ending, which was emotional both on- and off-camera.
"Let’s just say it was not hard to be upset in that scene," she added.