PARK CITY, Utah — Shia LaBeouf latest film was born in an unusual place — court-ordered rehab.

The actor spent time writing the script for his semi-autobiographical “Honey Boy” while he was being treated for substance abuse after a 2017 arrest.

“He wrote this script in rehab and actually sent me an email from there with the script,” said Israeli director Alma Har’el. “So it was pretty mind blowing. I couldn’t say no to that.”

LaBeouf premiered the film at the Sundance Film Festival on Jan. 25 in Park City, Utah. He didn’t speak with the media but posed alongside his mother, Shayna Saide, and fellow actors.

The former “Transformers” star plays an alcoholic and abusive father of a child actor, who is played at different ages by Noah Jupe (of “A Quiet Place”) and Lucas Hedges (“Boy Erased”).

“I think it was emotionally difficult for anybody to do what he did and I think nobody has ever done it before,” Har’el said. “He stepped into his own trauma and played his father in it — the most complicated relationship he’s ever had, that defined his life more than anything else.”