If there's any other storyteller who can get in line immediately behind George Lucas to take credit for the success of the "Star Wars" saga, it's filmmaker Lawrence Kasdan, who co-wrote the screenplays for "The Empire Strikes Back," "Return of the Jedi" and the most recent installment, "The Force Awakens" -- not to mention a few other you-might-have-seen-'em film credits including "Raiders of the Lost Ark" and his own directorial efforts including "Body Heat" and "The Big Chill."

RELATED: Han Solo ‘Star Wars’ Spinoff Draws Actors From Across the Galaxy

At 66 years-old, he's not yet done working in the galaxy far, far away. His next gig -- rumored to be his last Star Wars project -- finds him going back a bit longer ago to tell the story of how a young Han Solo became everyone's favorite space scoundrel. From the red carpet of the "Star Wars: The Force Awakens" Hollywood premiere, Kasdan explained to Spinoff Online what it was like getting into the right "Star Wars" headspace, and the nigh-impossible task of finding an actor to follow in Harrison Ford's icon-sized footsteps.

Spinoff Online: When you first got involved with "Star Wars" on the second movie, how easy was it for you to step into the George Lucas-style of storytelling and what you needed to do to make that work?

Lawrence Kasdan: Yeah, you know I had just finished writing "Raiders of the Lost Ark," and that was from an original idea with Steven [Spielberg] and George, so I had spent six months thinking about what would be the most fun movie we could come up with? When I was done, George said, you know, I need help on "Empire Strikes Back." And it wasn't much of a leap to say, "What's the most fun adventure movie we could write, to the second episode of the most popular movie of all-time?"

And on this film, did it come right back to you, immediately?

Right away. It did! It's such a big part of my life, and it doesn't really ever go away because the movies are so big. They're sort of always in the culture. Having written a lot of it, it's very natural for me. It was great to sit with J.J. [Abrams] and have a new voice, because he's such a big "Star Wars" fan that he very naturally entered that movie.

And you're not done with "Star Wars" yet. There's a little more to come.

Yes, and we're actually quite far along. My son [Jon] and I have written the story about young Han Solo. Chris Miller and Phil Lord are going to direct it, and we're still working on the script. It's still developing. It should be crazy because those guys are amazingly talented and you don't know what they're going to do. What they did with "LEGO" was amazing. So that should be a crazy movie.

And I understand the casting for young Han has gone wide.

Wide, wide!

I heard they've met with every young male actor in Hollywood. Have you been part of that process?

I've seen some of the stuff, but there's thousands. As you can imagine, it's a very good part. It's also a hard part to fill the shoes of. You have to say, what would Harrison have been like when he was much younger? There are only a few people like Harrison, ever, in movies. He's like Spencer Tracy. So who would be the young Harrison? They're a long way from finding that out yet.

Are you having fun writing it?

Oh yeah, it's been fun. He's my favorite character. It always is.

What's been the treat of writing with your son Jon on this particular project?

"Star Wars," the whole saga is about generations. It's about fathers and sons. Sometimes the fathers are good fathers, sometimes not a good father. It's about mothers and what's the effect of them? What do they give their children? It was really something to work with my son on a "Star Wars" story, and it was very emotional and stimulating and exciting. It's been good.

"Star Wars: The Force Awakens" opens in theaters this Friday, December 18.