Before the credits roll in Star Wars: The Force Awakens, Rey finds Luke Skywalker alone on Ahch-To. Turns out, who she arrives there with is just as important as why she goes there in the first place.

In a report from Entertainment Weekly, it’s revealed Star Wars: The Last Jedi director Rian Johnson requested the ending of The Force Awakens be changed because it made more narrative sense. At first, director J.J. Abrams had Rey showing up with BB-8 and Chewbacca. But in the final cut, BB-8 and R2-D2 are swapped.

“I asked if R2 could come with Rey, and if BB-8 could stay behind with the Resistance,” Johnson said. “Originally it was BB-8 who went with Rey, which makes sense for the story in a way. But I asked, ‘Can you do me this solid and switch the droids?’”

The whole idea behind switching the droids will make sense once The Last Jedi comes out later this year. Apparently, R2 (and Chewie) will play a big part in Luke’s grieving process, helping him overcome his self-exile. After all, they’re his oldest friends—and R2 was seemingly the last to interact with Luke before he disappeared.

“Figuring out where his head was at was the very first thing I had to do when writing the movie,” Johnson said. “I had to crack this. And it had to be something for me that first and foremost made sense. Why did Luke Skywalker go off to this island? That was the starting point, and that’s what the entire movie explores.”

Having R2 on Ahch-To while Rey trains will also be Johnson’s way of acknowledging Luke’s training in The Empire Strikes Back. So, it all comes full circle as we learn why Luke went into exile, and how him and Rey will begin a new age of the Jedi.

Star Wars: The Last Jedi hits theaters on December 15.