Watching Shia LaBeouf’s career trajectory has proved wildly entertaining. Beloved child star of Even Stevens, in 2007 he hit new levels of fame as the face of the (godawful) Transformers franchise. Since then he’s stealthily become something of an indie favourite, working with directors Lars Von Trier and Andrea Arnold, all the while committing to a series of baffling performance art projects – including that infamous “JUST DO IT” motivational monologue. He’s also been the subject of a viral choir performance of a song about being chased through the woods by “actual cannibal Shia LaBeouf”.

Courtesy of Sony Pictures.

Watching LaBeouf becoming one of the most-memed celebrities around, we tend to forget the other, far less funny headlines: tales of public outbursts and arrests, one of which in 2017 had him court-ordered to attend a drug rehab facility. There, he was diagnosed with PTSD resulting from a deeply troubled childhood – and it was there he started writing the fictionalised account of his experiences that would become Honey Boy. The result is a raw piece of autobiographical filmmaking that feels like a kind of therapy for both the audience and its writer.

Honey Boy begins in 2005, with blockbuster actor Otis Lort (Lucas Hedges) winding up in rehab after a drunken car accident. While dealing with his addiction and anger management issues, flashbacks which comprise most of the film take us back to 1995. Here 12-year-old Otis (Noah Jupe) is using his budding acting career to pay the bills for his eccentric father, played by LaBeouf himself; so, in effect, LaBeouf is playing his own father. Though this might all sound like just another headline-grabbing stunt, his brilliantly vulnerable performance is one of the film’s greatest strengths.

Courtesy of Sony Pictures.

The version of the father LaBeouf plays isn’t pretty. Once a rodeo clown, he’s now an abusive alcoholic. But he’s also Otis’s manager and number one fan, and initially seems to be his only friend. At their shoddy motel home, Otis is subjected to his father’s intricate manipulations; meanwhile, the polished suburban family of the Even Stevens-like show Otis appears in cruelly teases him with the love and care he’s missing out on.

Anyone who’s seen American Honey will know that LaBeouf can act. Here, he proves himself as an equally brilliant writer. It’s a hell of a balancing act he pulls off with this screenplay, which is simultaneously working as a “fuck you” and an “I forgive you” to a seemingly unforgivable father. Sometimes funny, sometimes upsetting, most of the time an uneasy blend of both – as in a remarkable scene when the younger Otis mimics his parents’ voices down the phone so as to facilitate a painful argument.

Alma Har’el’s direction is sensitive and inventive, with naturalistic handheld camerawork lending the film much of its intimacy. Lucas Hedges (escaped from the A24 basement and looking weirdly grown up) does well as the angsty older Otis struggling to come to terms with past trauma, although admittedly his scenes are totally eclipsed by Noah Jupe’s star-making turn. Watching the young Otis be subjected to his father’s abuse is rough at times, but this is ultimately a warm, satisfying and deeply cathartic film concerned with working through past traumas.

Honey Boy is out in cinemas now.