The collection of outtakes, included on the Blu-ray that hit stores this week, showcases just how many takes it took for Fisher to deliver the perfect slap to her co-star, who plays cocky rebel pilot Poe Dameron in the franchise.
"I remember the first day of shooting was a scene with Carrie,” Isaac told Colbert. "Often times that first day, the filmmaker's, everybody's trying to get the tone and figure it out and I remember it was a scene where I come up and talk to her and she's very upset with me and slaps me, and [director] Rian [Johnson] kept doing it over and over...It ended up being like 27 takes of Carrie just leaning in and every time she'd hit like a different spot on my face."
The gag reel also featured some funny moments from Daisy Ridley (Rey), John Boyega (Finn) and Kelly Marie Tran (Rose), but the cutest moment belongs to BB-8, who apparently had a pint-sized clone on set.
"You had a baby?" Boyega is heard asking the droid.
Here's hoping for a infant BB-8 appearance in the "Star Wars: Episode IX." In the meantime, check out the trailer for "Solo: A Star Wars Story" -- due out later this year -- if you haven't seen it yet.