A 'Star Wars' writer explains why it's been so hard to find the next young Han Solo actor

As "Star Wars: The Force Awakens" opens this week, the screenwriter of the film, Lawrence Kasdan, is busy putting the film out of his head. That's because he's begun work penning one of the franchise's most anticipated spin-offs, a young Han Solo movie.

Vulture caught up with Kasdan recently and asked him about how casting is going to find a young Solo. Around 2,500 actors have reportedly auditioned for the role.

There's perhaps no one better qualified to give an opinion, as Kasdan, along with writing "The Force Awakens," also did the scripts for "Empire Strikes Back," "Return of the Jedi," and "Raiders of the Lost Ark."

So, essentially, he's spent a good portion of his career coming up with dialogue for Harrison Ford.

"You want someone who isn't going to be exactly like Harrison, you want someone who suggests him," Kasdan said. "It's like when you adapt a book, and I've adapted a couple: You don't want to adapt it word for word, you want the essence to come through."

It's been reported that, in their wide search, Lucasfilm and the movie's directors Phil Lord and Chris Miller have seen both unknowns and known actors like Dave Franco ("Neighbors") and "Mr. Robot" star Rami Malek.

Whether the next Han Solo is an actor you've seen before or someone who just stepped foot into Hollywood, Kasdan thinks it's going to be tough to fill Ford's shoes.

"With Harrison, though, it's not easy to find someone with those kinds of qualities," he said. "He's like Spencer Tracy, and what does a young Spencer Tracy look like?"