More details are emerging about the firing of directors Phil Lord and Chris Miller from the upcoming Han Solo-centered "Star Wars" movie.

Since the duo was let go by Lucasfilm president Kathleen Kennedy last week, sources have revealed that there was a personality clash between the directors and the studio. The Hollywood Reporter has a new story detailing some of the "deep fundamental philosophical differences."

One source told THR that production department heads had begun to complain. "You have to make decisions much earlier than what they're used to. I don't know if it's because there were two of them but they were not decisive."

THR says tensions began to escalate in May when Lucasfilm replaced editor Chris Dickens with Oscar winner Pietro Scalia. They also hired an acting coach for star Alden Ehrenreich — not an unusual move, but for the late timing of it.

Still, Kennedy was apparently still troubled, as was Lawrence Kasdan, a writer and producer who penned the script with his son. He flew into London, but Lord and Miller were not willing to accept a "shadow director" in the vein of Tony Gilroy, who took over reshoots on "Rogue One" from Gareth Edwards.

Ron Howard has now been hired to finish up production, which will now extend a couple more months. He has reportedly been in touch with Lord and Miller, and a source said much of what they shot is "very usable."