"Star Wars: The Rise of Skywalker" doesn't arrive in theaters until December 20.
Disney and Lucasfilm go to great lengths to keep anticipated movies shrouded in secrecy, but Abrams told "Good Morning America" Monday that a real script ended up on eBay, reports variety.com.
"One of our actors, I won't say which one - I want to, but I won't - left it under their bed and it was found by someone who was cleaning their place," Abrams said.
He added: "It was then given to someone else who went to sell it on eBay."
A Disney employee spotted the for-sale item before anyone could get their hands on it and "got it back before it sold... With all the security, you have to be careful," Abrams said.
He also shared that 'Rise of Skywalker' went through routine re-shoots and wasn't completed until Sunday.
"You see something and think, 'That could be clearer, that could be a little better.' If you have ability to fix the piece, you take advantage of that," he said.
Being tasked to close out the nine-film Skywalker saga, Abrams said was "scary".
He said: "I care about it so much. It means a lot to a lot of people - us included. We felt the pressure, but the opportunity was always greater than the challenge."
But it would be impossible, he noted, to conclude the franchise set in a galaxy far, far away without Leia Organa, portrayed throughout the series by the late Carrie Fisher.
The actress died in 2016 before filming on "The Rise of Skywalker" began. However, there was unused footage from 2015's "Star Wars: The Force Awakens" that Abrams re-purposed to give Princess Leia a proper goodbye.
"We needed to have her in the movie somehow. We went back and looked at the footage and realized we could tell the story, we could create scenes with her. It's impossible for me to believe she's not here.
"We've been working with her in the editing room now for almost a year and she's vital, and she's there, she's funny, she's Leia in this movie. It's sort of surreal," he said.
( With inputs from IANS )