Rob Lowe just couldn’t catch a break from his son John Owen Lowe despite showing up to support him at the premiere of his new film Grace Point at its Los Angeles premiere on Thursday.

Rob, 60, was celebrating his 29-year-old son, who is prominently featured in the film opposite his former St. Elmo’s Fire costar Andrew McCarthy, 62.

The film is only the second credited feature John has acted in, and it marks his debut in a lead role.

But that didn’t stop the rising star from pranking his father by writing out his name on a portable white board, as if he wasn’t already a huge star.

The premiere turned out to be a family affair, as Rob was joined by his other son, Matthew Edward Lowe, 31.

Rob — whose brother Chad tragically lost his home in the recent LA fires —  looked sleek and as youthful as ever in an all-black ensemble.

Rob Lowe just couldn’t catch a break from his son John Owen Lowe (R) despite showing up to support him at the premiere of his new film Grace Point at its LA premiere on Thursday

Rob, 60, was celebrating his 29-year-old son, who is prominently featured in the film opposite his former St. Elmo’s Fire costar Andrew McCarthy, 62

He rocked a thin black sweater with a slim zip-up jacket and a set of tonal pinstripe trousers that didn’t quite match with the rest of his casual ensemble.

He completed the monochrome look with a set of shiny, chunky black boots, and he sported an admirably thick heard of dark hair.

Read More Rob Lowe details why it was a ‘nightmare’ working alongside son John Owen in their Netflix series

His prankster son John was the spitting image of the Brat Pack bad boy, and he fittingly opted for a leather jacket that made him look too cool for school.

He wore it over a black shirt with a low-enough collar to highlight his gold chain, and he looked extra stylish with a cool pair of high-waisted black pants and a slim black leather belt with a gold buckle.

John favored sleek black boots, and he sports a close-cropped mustache and a shaggy hair that only made him look more like his heartthrob father.

He stars with McCarthy 40 years after the veteran actor appeared with his father in the ensemble coming-of-age film St. Elmo’s Fire, which starred a bevy of other rising stars at the time, including Demi Moore, Emilio Estevez, Judd Nelson, Ally Sheedy, Mare Winningham and Andie MacDowell.

According to Grace Point’s official synopsis, John plays a young man struggling with drug abuse who travels to a remote rehab facility, only to find himself being chased by the small-town locals.

He’s accompanied to the rehab center by his father Winston (played by McCarthy), but the two are attacked at a gas station and Winston is wounded.

Rob looked sleek and as youthful as ever in an all-black ensemble with a thin sweater, slim zip-up jacket and tonal pinstripe pants

John pranked his father by writing out his name on a portable white board, as if he wasn’t already a huge star

John was the spitting image of the Brat Pack bad boy, and he fittingly opted for a leather jacket that made him look too cool for school

The premiere turned out to be a family affair, as Rob was joined by his other son, Matthew Edward Lowe, 31, who rocked a midnight blue jacket with a black fleece collar

John’s character flees for safety, but it’s up to him to try to rescue his father after the shocking altercation. 

He made an affectionate show of posing with his brother Matthew on the red carpet. 

The older sibling — whom Rob shares with his wife, the former makeup artist Sheryl Berkoff — was similarly attired to his family members.

He wore a lustrous midnight blue jacket with a black fleece collar, along with a black V-neck shirt, dark pants and a gray baseball cap.

John may have been trying to get back at his father at the premiere after Rob said last year that it was a ‘nightmare’ working with him on their Netflix series Unstable.

He joked that he had sent his son to Stanford — where he studied science technology — in hopes that he was going to ‘cure cancer,’ rather than ending up acting opposite him.

‘I mean, if he wanted to be an actor, he could have worked at Jamba Juice!’ he joked.