Carrie Fisher wrote some of her funniest étoile, star Wars: The Last Jedi lines 

universe much too soon but she had just enough time to add a few special touches to her last performance as Princess Leia in 

Warning: SPOILERS ahead for those who have NOT yet seen 

The actress, who died in December 2016 at the age of 60, left a lasting impression in the franchise, but she truly cemented her legacy in the latest entry in the

universe by writing her character’s scene stealing moments.

Director Rian Johnson, 44, told PEOPLE Fisher came up with many of her character’s scenes, including a funny moment in which she reunites with Mark Hamill‘s Luke Skywalker and points out that she changed her hairstyle.

“That was her,” Johnson said. “That was a Carrie Fisher line. Of course it was.”

That wasn’t the only line in the script that the talented screenwriter and author created. She also tackled a scene with Admiral Amilyn Holdo (Laura Dern) in which Leia says, “You go, I’ve said it enough,” in reference to the much loved saying, “May The Force Be With You.”

“In the scene with Holdo, that was Carrie,” Johnson said, speaking to his overall goal of adding more humor into the film, with Fisher’s help. “I think that as

fans, especially as adults, you can get into a mindset of wanting it to just be the heavy opera. And I don’t know, I was 10 years old when

came out. That was the perfect age for it. And the humor and the slight goofiness of it also, and kind of the slight free-wheeling feel of it, and how it’s unafraid to have fun, that to me is essential.”

Johnson added that “every single part of her performance” was imbued with Fisher’s ideas, which she gave him while filming.

“I would sit down with her and she would just give me … After an hour, I would have filled up pages and pages writing down the notes and one-liners that she would pitch,” he said. “And so we tried to work them in whenever we could.”

One person who will surely miss Fisher is Hamill, who told PEOPLE their bond as brother and sister was as real off-screen as it was on.

“I loved her, but we fought. We had rows where we didn’t speak to each other. We always ran really hot and cold. I mean, when you saw her, you just hugged her, it was the greatest thing to see that you could imagine. But she was a handful,” Hamill said. “I mean, she was engaging, she was hilarious, she was fun to hang out with.”

Hamill admitted it was “difficult for me to accept her in the past tense,” and believes she is “wonderful in the movie.”

followed them throughout their film and television careers, it was Fisher who encouraged Hamill to embrace his fame as Luke Skywalker.

“It took me a while but I came to really enjoy it in a way that I couldn’t have enjoyed it in my 20s,” he said, adding Fisher had told him, “C’mon Mark, I’m Princess Leia, you’re Luke Skywalker, get over it, enjoy it.”

He continued, “I learned so much from her. I’ll never stop missing her.”